Thursday, December 22, 2011

The Never Ending Story

Well, not quite never ending but it sometimes feels that way.  

I adjusted the pots on the stepper controllers last night.  It fixed all my problems with the steppers except for the Y-axis which just sat still and jerked a bit no matter what I tried.  I eventually moved the motor over to one of the other controllers and found that it worked fine so I guess I have one bad controller.  I actually thought about ordering a couple of spare Stepsticks when I ordered the Sanguinololu but decided against it so now I have to wait again for a delivery.  The genetic predisposition to being a cheap bastard which I inherited from my Scottish ancestors has undone me again.

The good news is that everything else seems to be working finally.  Extruder, steppers and hot end are functioning as they should so I am able to do a few things while I wait.  The opto-endstops are not working yet but that is because I have not yet soldered the bridge for the 5v power to them.  I also need to clean up all of my wiring but I was waiting to do that until I got everything working.  After I do that I am going to switch the controller for the Z-axis to the Y and then I can do a couple of tests while I wait:
  • Lay down a line in a single layer so I can confirm that it is extruding the correct length of filament.
  • Lay down a square in a single layer to confirm that everything is square.  Should get right angles at the corners and sides of the same length in both the X and Y directions.
  • Lay down some complex curves in a single layer just to confirm that ethe X and Y axis are moving as they should and are coordinated properly with the extruder.
Since the Stepsticks are coming from the Netherlands I expect it to be a couple of weeks yet before I will be able to build anything but success is definitely in sight at last.

Wednesday, December 21, 2011

By George, I think I've Got It!

Just a quick update.  

Based on some online posts that I found, I believe that I have identified the problem with my steppers.  I think I just have to adjust the current potentiometers on the Pololu driver cards.  I haven't had time to try it yet, hopefully tonight.  If this works I will have solved my last problem with the machine itself.  Very exciting.

Monday, December 19, 2011

Hot Damn! Melted Plastic at last!

Over the weekend I finished re-assembling the Mendel and tried it out.  The Sanguionololu works great and so does the Sprinter firmware although I still expect to have a lot of tweaking for my specific machine.   Here's a quick pic of my first mess of plastic:

I think I will keep this blob on my desk as a post modernist sculpture

At first I could not get the filament to feed into the extruder.  I was trying to get it in by hand-turning the gear on the wade's extruder but it just didn't seem to be able to pick it up.  It was late and I was just going to give it up for the night when I realized that I was turning the gear the wrong way!  As soon as I turned it the other way the filament loaded into the hot end easily.  One more boneheaded move among many.

With the ATX power supply and the single board electronics my wiring is much cleaner.  I still seem to have a problem with my steppers though.  The X axis moves very slowly and the Y and Z axis don't move at all.  They just hum and jerk a bit.  I think that I may have them wired wrong but it was getting too late to get into troubleshooting last night so I will check it out tonight.

But, in general, it looks like I am finally ready to build some things.  Life is good.

Monday, December 5, 2011

Finally, Some Good News!

I wired up the Sanguinololu board last night and things went very well.  I jumpered the power enable pins on my new ATX power supply and then clipped the connector off of the 4 wire power connector and twisted the two power and two grounds wires together.  These were inserted in the screw terminals on the Sanquinololu board and then I plugged in the USB cable.  I got a steady green light so it looked like everything was ready to test.

I loaded up the Sprinter firmware that I had modified for my Mendel with no problems.  Then I confirmed that Pronterface can connect to the board.  I probably still have to do a lot of tweaking of the firmware but that can wait until I have a test print to use as a baseline.

My extruder is still disassembled from fixing the broken thermistor wire but I was able to wire it up on the bench to test it.  I had been holding off on reassembling it and mounting it back on the machine until I could confirm that it was working correctly since it is a major pain in the ass to remove.  I removed the 4 pin connector that came with my Botmill extruder and replaced it with two 2 pin connectors.  The heater and thermistor connectors on the Sanguinololu are on opposite ends of the board so their arrangement just wouldn't work.  After connecting with Pronterface the temp reported as 25C, which is about correct for my basement workshop so I went ahead and sent a command to heat up to 185C (PLA melting temp).  The heater worked and the thermistor immediately began reporting the correct temps as it rose  I confirmed that it heated up to the correct temperature and that it then started the regular on-off switching cycle in order to keep the temp stable.  Being fairly certain that I could melt plastic safely I then moved on to the steppers.

The Sanguinololu board expects 4 pin connectors and my old boards had screw terminals so I can't hook up the steppers until I get the correct connectors.   I had bought some locally only to find that I had the wrong ones.  I have a set coming in the mail but they have not arrived yet.  Luckily I have one stepper that arrived with the correct connector already attached so I used that one for testing.  I attached it to the extruder controller  and sent a command to extrude 5 mm.  The stepper kicked in and ran for what seemed to be the correct time period.  Hot Damn!

I then moved the motor to each of the X, Y, and Z controllers in sequence and tested them with the jog commands.  All seemed to be working correctly.  The only thing that I did not test was the opto-endstops.  I have to solder a joint between two pads on the board in order to set the voltage for them.  In my case this is 5v but I forgot to do it before I hooked everything up so it will have to wait until I take everything apart again prior to the final assembly..

So it looks like I am finally ready to print.  As soon as my connectors arrive I can do the final hookups of the steppers and move on the the really interesting part of this whole thing, the printing!

Tuesday, November 29, 2011

New Electronics

Sorry I've been gone for a while.  I finally threw up my hands and gave up on the Techzone electronics.  It seemed that, no matter what I did, I could not get any firmware to work correctly on it.  When I looked online I found that very few people were working with or supporting it so there wasn't the community that I needed to help me through it.  Given that sad situation I ordered a Sanguinololu and I have been waiting for it to arrive.

The new board arrived last night so I am back on track.  I will be using the Sprinter firmware since it seems to be fairly mature and has a good support community.  I hope to have time tonight to get things hooked up and tested.

Tuesday, November 8, 2011

More Progress, Same Problem

Last night I modified the heated bed and got it installed.  I attached the silicon heater element to the bottom (it's a simple peel and stick) so I just need to install a thermistor and wire it up to my control box and that will be ready to go.

Of course, a heated bed does me no good unless I can get this thing to extrude.  I switched out the thermistor again and got the same result.  Temp reads as 875 degrees at room temperature so the heater does not kick in.  I know that the thermistor is fine (I guess the previous one was OK as well) so I have another problem.  It wasn't until this morning on the way to work that I realized that I probably have the wrong temperature table in my firmware.  I will check that next.

Monday, November 7, 2011

Replacing the Thermistor

I finally got some free time to work on the Mendel yesterday.  I removed the extruder and replaced the thermistor with a spare one that I had laying around.  It involved carefully cutting away the Kapton tape and removing the thermistor leads from the crimped fitting that Botmill uses to connect it.  Not an extremely complicated procedure and it only took me about 20 minutes to replace it and re-crimp the connectors and tape the new thermistor in place.

I thought that I would do some testing prior to bolting the x-carriage back on the Mendel and it's a good thing that I did.  The temp showed as 875C so the heater never cut in.  When I checked the resistance of the thermistor I found it to be about 115K Ohms rather than the 80K that it should be.  Should have checked it before I installed it.  Either it is a bad thermistor or I picked up one with the wrong values at some point.  Luckily I have another one and it tests at the correct 80K so I will switch it out again.

Since I was dismantling things anyway I decided to switch out the build surface for the aluminum one that I bought to prepare for adding heating to it.  I removed the old one and then found that the aluminum plate blocked two of the holes in the plywood frame piece.  I will drill them out tonight.

I also made a cable with two female connectors so I could add a ground cable between the main and extruder boards.   I don't know if my problems with the extruder motor are due to grounding issues but this certainly can't hurt.

Thursday, October 20, 2011

A Quick Update

Just a short post here.  

I have discovered the source of at least one of my problems.  One of the leads on my thermistor is broken.  I think it may have burned through when I had the thermistor and the heater wired backwards.  In any rate, the thermistor reads as an open circuit and is definitely dead.  I will have to remove the extruder and dismantle the hot end to replace it.

I have also made up a ground wire to run between the main and extruder boards.  hopefully that will help to clean up the signals between the two boards and get the instructions to the extruder cleanly.

Tuesday, October 11, 2011

More progress - still no extrusion.

I didn't get as much time this weekend as I expected.  The furniture moving, along with the cooking and the Turkey Torpor, kept me out of the lab for most of it.

I did, however, get time to re-do the wiring for 12v power to the stepper controllers and the extruder board.  I had decided that poor wiring was causing some of my problems.  The issues with the steppers corelated with their distance from the power source. X and Y moved OK, Z was intermittent and the extruder didn't work at all.  This was due to my crappy job of wiring that caused more grounding problems as the power was passed down the line.  I rewired the whole thing and the problems disappeared.  I now have all 3 axis moving just fine with no squealing steppers and no pauses.

The extruder is still a problem though.  The motor doesn't do anything at all, which is odd since, last week, it was not moving but was squealing, indicating that it was getting some power when I sent a command.  Probably still a wiring issue.  Also, I noticed that the heater did not seem to shut off when I set the temperature to 0.  It seems to be getting power all the time so I guess I still have an issue with it.  I will get my IR thermometer from the garage so I can tell for sure what it is doing.

I will be logging in to the RepRap IRC chat tonight to see if someone can give me a fix for these items.  Progress is slow but at least it is progress.

Friday, October 7, 2011

Progress - in less than 10 minutes!

I only had about 10 minutes last night to work on the Mendel but I came away happy.  I had figured out that my firmware was probably not correct for my boards so I downloaded a new version specifically for the techzone hardware.  I loaded it up on both the main board and the extruder and got some great results.

All 3 axis are now working, although the Z axis seems to be intermittent. Sometimes it doesn't move when I jog it and the stepper makes a squealing sound as if it is jammed or something.  A couple of times it moved just fine though so I think that this is probably a hardware issue (something stuck in the gears etc.).  I will take a look at it tonight.  The correct commands are definitely getting to the steppers now though.  

Also, the hot end of the extruder is heating up just fine and the thermistor is passing good data back to the board.  I was using Pronterface last night and could easily track the temp as it went up.

I didn't have any filament in the machine but I hit "extrude 5 mm" a couple of times to see if the extruder stepper would rotate.  It didn't move so that is my biggest concern at the moment.  I set the desired temp to 0 and it still wouldn't move so I guess it is not something in the firmware as I had suspected.  I may have the stepper wired incorrectly but I didn't have time to check last night.

This will be a long weekend here in Canada for Thanksgiving and it is supposed to rain all weekend.  That means that I should have lots of time to work the bugs out and get something extruded.  I also have to move our entire home office down to the basement so my wife can have the spare room to set up an office for her new accounting business but what the heck, I have three whole days!

Tuesday, October 4, 2011

I'm an Idiot!

I got my old Linux tablet working again and connected to the Reprap.  Guess what I discovered?  The damn thing can't connect.  This indicated that the problem had nothing to do with my Windows workstation at all and was probably hardware related.  I pulled out the 6 conductor cable between the main board and the USB/TTY adapter and, sure enough, one of the leads was dead between the two connectors.  I made up a new cable and "voila" both Pronterface and Repsnapper can now connect with no problems.

I have the X and Y axis moving fine but my Z axis won't move anymore.  Probably more of my sloppy wiring.  The hot end is heating up but I don't seem to be getting any temp readings back from the thermistor.  Again, probably a hardware problem.

I tried to sending a command to the extruder but the motor didn't do anything.  I only thought afterward that the software may prevent it from running until the hot end reaches operating temperature to prevent damage from trying to push un-melted filament through the tip.  I will check the code for this.

So it looks like I am finally able to proceed with final debugging and getting Mendel working.  There's a lesson to be learned here - don't assume anything.  Just because things were working on the Linux tablet didn't automatically rule out hardware problems being the culprit.  It was really my tunnel vision on the ports that kept me from examining other possible issues earlier.

Oh well, Onward to Victory!!

Tuesday, September 27, 2011

A Possible Solution

I have been looking through the FDTI site and I may have identified my problem.  There are two types of drivers for the chip on the Techzone board - VCP drivers and D2XX drivers.  The VCP drivers set up a virtual COM port and those are the ones that I installed.  The D2XX drivers allow the software to access the USB connection directly using a DLL.

It seems possible that I should have  been using the D2XX drivers instead of the VCP ones that I installed on my workstation.  It is certainly worth a try anyway.  I will install the other set of drivers tonight and see what happens.

The Continuing Story....

I now have Repsnapper installed and working.  Unfortunately it has made no difference in my ability to connect to the Mendel.  Although Pronterface was telling me that the port was unavailable, Repsnapper tells me that it is timing out while trying to connect but has no further information.  This happens whether I attempt to connect using the original COM! port on the machine or the virtual COM3 port created by the USB/TTY interface

I am wondering if the whole problem lies with the drivers that I installed for the FTDI USB/TTY chip that is used on the Techzone board.  I am going to see if there are older versions available.

This worked so easily under Linux.  It is very frustrating to be this close to a working machine and be stopped once again.

Thursday, September 22, 2011

Connect Problem

I have tried several times to get Pronterface to talk to the Mendel but I get a message stating that it "cannot open port COM3, access is denied".  I believe that this is due to a problem in the pronterface code.  The Reprap Host Software on my Linux machine had no problem connecting.  I think that it is something to do with the communications between the PC and the USB/TTY adapter that leads Pronterface to believe that the COM port has already been opened by another application.  I have not been able to find any resolution for this in the various forums.

I am going to install Repsnapper tonight and see if it is able to connect.  Good thing that there are a number of options out there for host software.

Tuesday, September 20, 2011

Back Again!

Well, after another extensive period of procrastination I am finally back to work on the RepRap.  I have been at it for a couple of nights and have managed to finish all the wiring so I am back to fighting with the software.

I installed the reprap host on my new/old desktop but I can't seem to get it to run.  It is probably due to version conflicts with Java but, after messing with it for a while, I decided to switch over to using Pronterface and Sfact as my toolchain.  They both installed easily and run fine under windows.

I initially had some problems loading the firmware from the Windows machine until I realized that I had to load a set of drivers for the Techzone USB/Serial board.  I guess they were already available on the Linux OS that I was using on my tablet because I am sure that I didn't have to manually install them there.  (I am sticking to WinXP on the desktop, not because I like it but because I don't have Linux drivers for the wireless card I have on it).  Once the desktop was able to talk to the Arduino I had no problem installing the firmware on the main board and the extruder.

That was where I left off last night.  I was not able to get the steppers running  but I think that was due to my ignorance of Pronterface.  I will go through some documentation today and give it another try when I know what I am doing.

I expect that there may still be some adjustments to the firmware but I will have to get things running in order to know for sure.

Perhaps I will finally extrude.

Tuesday, May 31, 2011

A Little Progress on a Couple of Fronts

Well, I am still not printing.  That is more due to my crazy life than any real issues with the Mendel.  I have managed to change jobs, attend a funeral/family reunion, get my daughter off to New York on her class trip, make a couple of road trips for my work, arrange for repairs on the house, fix both cars and see my wife through a bad stretch with her (former) employers.  I'm pooped!  What I have not managed to do is finish assembling my extruder.

However, a couple of weeks ago I anticipated this situation and ordered a fully assembled extruder from Botmill.  After I placed the order I happened on a lengthy exchange on the Reprap forum where a number of folks complained of poor customer service from Botmill so I was not sure what to expect.  It all turned out well though.  I received an acknowledgement of the purchase within 10 minutes and the unit was shipped within 48 hrs.  They sent me another notice when it shipped along with a tracking number.  It arrived within a week of the order and it is exactly as advertised.  A very nice little unit based on Wade's extruder.  It even came attached to an upper x-carriage so now I have 2.

I realized when I started to install it that I had neglected to install the captive nuts for the extruder bolts in my upper x-carriage part so I will have to dismantle the x-carriage.  Bummer!  However, it was going to be necessary anyway.  As it turns out, one of the angled bolts holding the 45 degree bearings on the lower carriage is too long and interferes with the extruder so I will have to cut it down.  I could cut it in place but I don't want to be spraying metal filings all over the Mendel and into my steppers.

I also have my new (used) computer installed now.  I bought a cheap monitor for $100 and an even cheaper wireless card for $30.00 and installed a dual boot OS with WinXP and Ubuntu 11.04.  Unfortunately I can only get the wireless drivers to work in Windows.  I will run the Mendel using the Reprap Host Software on WinXP until I get that situation resolved because I hate running disks back and forth from my office upstairs to the Lab (that's what my wife calls it, complete with the capital L)

On another front I seem to have finally found someone to cut the parts I need for the chassis of the DIYLILCNC router.  A guy in Alberta is offering to laser cut them from 1/4" MDF for a very reasonable price.  I will post his contact information on the builders forum once I have received the parts and can evaluate their quality.  I have a number of additional parts to source before I can start the build but the cut sheet parts are the hardest to get hold of.  Very similar to the Reprap situation last year except that it isn't the scarcity but the cost of laser cutting that is the difficulty.  The parts comprise most of a 4*8 sheet of mdf so there is a lot of cutting and all my local laser cutters wanted over $1000 to do it.

Hopefully I will actually get some work done this week and will have something to take pictures of shortly.

Tuesday, May 3, 2011

Still Waiting!

Just a quick update.  I am still waiting for my last stepper motor to arrive so I can complete the extruder.  I have been puttering on the control box while I wait.  It will contain the bed heater, power supply and emergency cuttoff switch.

Wednesday, April 20, 2011

It Works!

Last night I checked the extruder settings and, sure enough, the target temp was set to 2 but the extruder temp showed as 1 even without any thermistor attached.  I changed the setting for target temp to 0 and the whole machine started working just fine.  It was very exciting to watch it go through the motions of printing a frame vertex.  I took some video but I have not been able to get it to upload to Blogger.  I am trying to reduce the size and convert it to other formats but no luck so far.  I may try uploading it to YouTube first.

Tuesday, April 19, 2011

One More Baby Step Forward (and a really cool resin printer)

I managed to change my firmware settings last night so I now have all three axis moving correctly.  I hit "home" and watched all three move at the same time.  Very inspiring.

Then I decided that I would load up a Gcode file and get things moving, even though my extruder is still on the workbench.  It was a good exercise since I hadn't even looked at the user manual for the host software.  I managed to get the Gcode generated and loaded up but when I hit "print" it just sat there with the "estimated time to print" moving upward into the hundreds and then thousands of hours.  I had to think about it for a while but I realized today that it was probably waiting for the extruder to reach operating temperature.  I am going to try again this evening but first I will set the working temperature for the hot end to 0.

Here is a site that everyone should see.  This guy has built his own 3d printer but it does not use the fused deposition technique of the Repraps.  It harks back to the original 3d printers in that it uses a polymer resin that is hardened layer by layer using UV light.  I don't know the details of his hardware but the resolution is really remarkable.  The flute in these pictures is playable.  He is trying to get plans or kits together (not too sure exactly where he is going yet) so this is definitely a site to put on your watch list.

Alien Skull designed by Avinash Hegde at

Playable flute

Monday, April 18, 2011

And Now for Something Completely Different

One of the things that delayed my work on the Mendel over the last week or so was that my trusty HP TC1100 tablet computer was out of action.  This was caused by my preparations to get another project underway after the Reprap is finished.

This is a small CNC router called the DIYLILCNC.  It is open source and the plans are freely available on their website.  It has a cutting area of 12"x14"x2".  I am going to build one to complement the Reprap since it will be great for cutting small parts out of flat stock.  The DIYLILCNC is constructed mostly out of stressed hardboard, called Masonite in some places.  A full 4x8 sheet is required but it is very inexpensive and the parts are simply bolted together, much like a Mendel.  All in all it is a very elegant little design and has the advantage of being complete, tested, and well documented.  The parts are designed to be laser cut but, like Repraps, the user community has already begun their own redesigns.  Someone has posted a set of cut patterns optimised for a CNC router.  Since my daughter's school has a large CNC router setup I plan on doing some horse trading for the cutting service.  Perhaps I can do a presentation on the Mendel for the shop students.

Instead of designing their own electronics hardware the lilcnc team simply used one of the commercial 3 axis kits that are now available from a number of sources.  They also use an easily acquired Dremel tool as the cutter.  I ordered my motors, electronics and power supply as a kit from China.  I have no idea what the quality will be like but the price was worth taking a chance on (about $200 including shipping).  The three NEMA 23 motors are slightly less powerful than the ones called for in the DIYLILCNC plans but they should do the job.

As far as my tablet being out of action - I tried to load an application called EMC2.  It is an open source CNC control application and is the one most commonly used if you can't afford the (very expensive) commercial alternatives.  Unfortunately, when I loaded it up it somehow corrupted my Nvidea drivers and I was unable to even boot the machine.  It took the better part of a week to get things going again.  Since I use that machine to run the Mendel it really slowed down the work on the current project.  Perhaps I should stick to one project at a time.  In any case, I discovered while troubleshooting the problem that the folks at the EMC2 website do not recommend running it on tablets or laptops since it is a realtime control program and the older laptop technology usually can't keep up with the cutter and will start dropping instructions.  Oh well, Live and Learn.

More Progress

I did a lot of work on small things this weekend.  I finally greased the rails, adjusted the endstop tabs so they meet the endstops correctly, reloaded the firmware, and rewired the 12v system (it was very sloppy and would have caused problems eventually).

I now have all 3 axis moving smoothly.  My only problem is that the X and Y axis move in reverse.  They worked fine when I was jogging them but as soon as I tried to home them they shot to the wrong end of the rails.  I don't have my control box wired up yet so I had no emergency stop button but I had my hand on the plug for the power brick so I was able to pull it and shut things down without any damage.  I tried to reverse the direction of those two axis in the firmware but it had no effect.  I suppose I have to dig deeper into the code.  Either that or change the wiring of the motors themselves.  Strangely, the Z axis moves correctly and I can home it without any problems.

I also worked quite a bit on my extruder.  The hot end is assembled as well as most of the rest of the parts.  I just need to epoxy the peek insulator into the main body of the extruder.  My main problem now is that I still can't get the gears off of my used stepper motor.  I am going to order a new one today and I will just have to wait for it to arrive.

I will start to assemble my control box this week.  It will clean up my workbench a bit and I won't have to pull the plug anymore to shut the steppers off.  It will only contain the power brick, a lighted on/off switch, for the 12v  system, the emergency cuttoff, and the PID for my heated bed but keeping those things neat will be worth the effort.

Monday, April 4, 2011

Some Progress But .....

Well, I just had a whole week off work but I am still not printing. Why, you ask? Because I am a lazy so-and-so. Also because there always seem to be a hundred things that need to be done before I can get to the Reprap work.

I have made some progress though. I have assembled both of my MakerGear Heatcores. They seem to be working perfectly. A small problem with them is that they did not come with the Molex connector that should be attached. I think that the later kits include it (it is shown in the assembly instructions on their website) but mine did not. Remember that I bought my kits last spring so they are from the early lots, things have been improved since then.

I also began assembling the geared extruder. I don't have bolts long enough for some of the assembly steps so I have been cutting lengths of threaded rod and placing a nylok nut on one end. It seems to work fine and it allows me to customize the lengths to whatever I need.

I also discovered another oversight on my part. When I ditched my plan to use a set of used stepper motors for the Mendel I purchased some new ones. Unfortunately they came in a set of three so I don't have one for the extruder. I will have to use one of the second hand motors for this but that means that I have to solve my problem with the gear that is stuck on the shaft. If I can't find a way to remove it without damaging the shaft or the motor I will have to buy another new one and wait for it to arrive. I guess that would not be too serious a problem since I am taking so long with these final steps but I will try to get the old gear off first.

More pictures and some video of the axis moving when I post next time.

Saturday, March 26, 2011

It's Alive! Alive!

Great progress. The Reprap software is running properly on my laptop, it is talking to the main board which is talking to the stepper controllers. All 3 axis are now moving although I have a problem with the Z axis. It only moves up, not down. I think that the belt is too tight so I will do some troubleshooting tomorrow. I have started to assemble the extruder and, since I have a week off now, I should be extruding plastic within a few days.


Thursday, March 17, 2011

Great Joy in Mudville!

Good news. My new main board arrived from Techzone yesterday and I immediately sequestered myself in the fortress of Solitude (formerly the daughter's playroom) to check it out.

I plugged the USB/ITE cable in and, with breathless antici..........pation, compiled and attempted to download the firmware. It was apparent from the start that something new was going on since the red LED began blinking along with the steady green one that I have been seeing all along. The board behaved exactly as described in all the online resources and the firmware loaded successfully. The red LED then settled down into a steady 1 Hz blink just as it should.

So, long story short, I had a bad board. I don't believe that the board was bad when I received it. There were a set of check marks on the back indicating that it had passed all the testing prior to shipping. I think I may have sent some current through it incorrectly when I was figuring out how to wire everything up. Techzone was not the culprit here, just my own clumsiness (again).

I have a long weekend now so I hope to work out all the remaining small things and have the beast up and running by Sunday. As long as family responsibilities don't get in the way. Amazingly, my wife has been very understanding, and tonight she actually referred to the Mendel as my "Happiness Machine" when I was coming down here to work on it!

Tuesday, March 15, 2011

Big News! AdderFab!

The University of Washington has become a major source of innovation in the use of powder bed printers with new and inexpensive materials. Professor Mark Ganter and his students have been experimenting for several years and have produced some amazing results. Today they tease us with the announcement of something really fantastic - the AdderFab 3d printer. It is a powder bed printer using an off the shelf HP print cartridge and assembled using fabbed parts which are very similar to Mendel parts.

From their video it is apparent that AdderFab prints quite slowly at the moment but Mark says that they will be working over the next few months to speed it up before releasing the design as an open source project. Most of the home built printers of this type have used the whole X-carriage from a commercial inkjet printer which has both advantages and disadvantages. On the upside the X axis movement can be handled by the existing printer carriage hardware but it also means that every printer has a unique design if it uses a different printer as its' parts source. The design of a standard X carriage, once the bugs are worked out, will make this design much more reproduceable.

This is exactly what I was planning on doing as my next project after I got the Mendel working. Of course, with my limited engineering skills, I would not have produced anything as nice as what I see from the Open3DP group so I will be happy to build their design and avoid having to figure things out on my own.

Having both machines raises the possibility of creating items that are assembled of parts printed in multiple materials - plastic parts from the mendel and ceramic or glass parts produced by the AdderFab.

Monday, March 7, 2011

Some Progress But ...

I have managed to make a bit of progress but I still don't have the electronics working properly.

I lost a couple of weeks on other projects. I upgraded all of the PC's in our house to windows 7 (except for my trusty HP tablet which will stay on Ubuntyu Linux) and fought my way through the various issues that cropped up. Then I moved my entire shop from the large family room in the basement to our spare bedroom. The room was used as a playroom by our daughter but, since she is now 16, it is available for other purposes. It took a couple of days to get everything moved and organized but I am finally ready to proceed.

I sat down last night and worked on the firmware again. I had been using version 22 of the Arduino IDE but the various forums recommended going back to version 18 to solve my problems. As soon as I started using the earlier version I had some success. Both the G-code Interpreter and the Extruder firmware compiled immediately.

I was able to load the extruder firmware onto the board and it was really satisfying to see the green LED's start flashing as it was running. This proves that my USB board and the 6 wire cable that I made up are both working correctly and that the IDE is able to communicate with the board using that path. Unfortunately none of this made any difference when it came to loading firmware on the Sanguino board. All I get is a steady power light when I plug in the USB cable. When I attempt to upload the firmware I get a messages from the IDE that indicate that everything works fine but there is no indication that anything is getting to the board. The power light stays green but there is no flashing or blinking to indicate that anything is loading or running. No amount of playing with the reset switch has any effect at all.

I was interrupted last night and didn't get time to do much experimenting so I will try again tonight and see what happens. In any case, I am getting closer to having a functional machine.

Also, I ordered a couple of additional motor controller boards (I fried one) and some additional opto-endstops. If I don't fry any of my endstops I can use the new ones on my next project.

Friday, February 18, 2011

Quick update

I have still not managed to get the firmware loaded on the main board. Despite changing the baud rate and messing about with timing of the restart it continues to do nothing. What is strange is that the Arduino IDE reports a successful upload with no error messages. The fact that the LED does not flash when I push the restart button leads me to believe that there is something wrong with the board itself.

I managed to contact Lambert from Techzone Communications and he was very helpful in giving me a few suggestions. None of them has produced results unfortunately. One thing that he suggested is that I use Repsnapper as my host software instead of Reprap Host. I haven't gotten Repsnapper working on my tablet yet but it is not yet a priority since I am pretty positive that nothing is being loaded on the Sanguino by the IDE. Unlike Reprap Host, which is written in Java, Repsnapper is a C program and Lambert feels that it is more stable. Time will tell.

I am going to move on from the main board and try to load the firmware on the extruder board this weekend. Even if it doesn't work perhaps it will give me some more information to work with.

On a more positive note, I received my silicon heater pad and the PID controller for same. I will be ready to proceed with my heated build platform whenever I get the Mendel running. I also received my new Soldering station with both a soldering iron and a heat gun included. See Below:

Pretty Cool Eh? It also comes with these extras:

I have been using a fixed temp pencil iron up until now and I just can't wait to melt some solder with this thing.

A major task this weekend, which is a three day weekend for us Saskatchewanians, is to clean up the spare room downstairs. After we make some room in there I am going to move in all of my workbenches and gear. It will give me the room to set things up properly and get organized.

Wednesday, February 9, 2011

Into the Valley of Troubleshooting Hell I Ride!

After much messing around I have managed to get the GCode Interpreter to compile on my old Linux Tablet PC. I am running Ubuntu Linux but I had neglected to download all of the various AVR modules that I needed so I wasted a couple of days digging through the code for the compile error and searching the online forums for help that I didn't really need. At least I feel a bit like a programmer again. It has been a good 10 or 15 years since I looked through any code. I am going to have to get used to it

I was amazed, when I got into it, at the amount of settings and tables that exist in the Interpreter code. I will have to go through it again before I run the machine to ensure that I have things like the thermistor or thermocouple tables set correctly. I will double-check the accuracy of their readings with my handy dandy infrared thermometer the first time I power up the extruder. No Reprapper should be without one.

The next step is to get the software loaded onto the Sanquino main board. Unfortunately I have been unable to get this to work. The Arduino software tells me that it is uploading and that the upload is complete but there is no indication from the board that anything is happening. The LED stays a steady green. I have tried the various combinations of clicking on the upload icon and pressing the restart button on the Sanguino that are suggested on the Reprap Wiki with no results. There is always the possibility that I have a hardware problem with the cable I made for connecting to the board so I will check it with my multimeter. I will also do some searching online for other folks suggestions. Oh, before you ask, the restart pins are permanently jumpered on the Techzone board.

I have been off work this week with another bout of illness so this is all I have been able to do. I am hoping for better now that I am on my feet again.

Monday, February 7, 2011

Green Lights!

Well, i finished wiring the Mendel this weekend. I only hooked up one of the stepper drivers and disconnected the extruder board just in case. Then I plugged in the USB cable and ..... Green Light! The main board LED lit up just fine. Since I was feeling foolishly overconfident I also plugged in the 12v source for the stepper and got a green light on that board as well. Unfortunately that is as far as I got.

The green light on the stepper board faded out over about 5 to 10 seconds. When I disconnect and reconnect the power I get the same reaction - first a bright LED which fades quickly to nothing. I have no idea what is happening there.

The Main board, on the other hand, is a different problem. There didn't seem to be any communication between it and my laptop so I went back and re-read a lot of the Techzone information. It turns out that the firmware loaded prior to shipping is for the Makerbot so i will have to load up the Reprap firmware before I can go any farther. Given my limited tech savvy that is harder than it sounds but I am working on it. I have the Arduino IDE and Sanguino extensions downloaded and tonight I will try to figure out how to get the firmware loaded.

Thursday, February 3, 2011

Some Thoughts on the future

Since my project is nearing completion I have begun to consider where I will take it from here. I quickly came up with the following list of projects that I would like to work on. They are not in order of priority and some may get dropped completely later but they are the ones that are spinning around in my head currently

Tentative list of Projects using the Reprap – Things that would utilize parts printed on the Mendel.

  1. Build a powder style printer. A modified version of the Mendel Y-axis hardware could be used to move a re purposed inkjet printer carriage. The X-axis hardware from the printer would be used as-is. Utilizing the existing steel bar/skate bearings/printed parts design would save time and make it easier for others to replicate it. The bins for the Z-axis would have to be designed from scratch but the electronics could be as straightforward as an Arduino and a set of Pololu drivers.

  2. Print spare parts for the Reprap. This is a no-brainer and should be the first set of parts printed by any reprap owner.

  3. Print a Prusa Mendel for Dissidence. He has been an inspiration and a good sounding board for ideas. He deserves a Mendel and will also provide a good backup for me in case I break a part and don’t have a replacement on hand.

  4. Build a Prusa Mendel to donate to my daughter’s school. I would like to help raise awareness of the amateur rapid prototyping movement. They have great mechanical and woodworking shops at the high school and I’m sure they could make great use of one of these machines. They already have a large CNC router table so the instructors are relatively familiar with the basic principles involved. Actually, depending on performance, I might keep the Prusa and donate my original Mendel.

  5. Make a set of adapters for the relays in my Jaguar. I am replacing the belt driven fan in my Jaguar XJS with a set of electrical fans. This requires me to add two new relays to the wiring. Unfortunately the relays that come with the kit do not match the mounting brackets in the car. I would like to print a set of adapters that clip onto the mounting bracket in the car with one side and onto the relays with the other. These will probably have to be made in ABS since the Jaguar V12 engine produces a great deal of heat.

  6. Build something large. I’m not exactly sure what this would be but I would like to produce something to really demonstrate the capabilities of the Reprap and that would mean pushing the boundaries of what it can do. I was speculating on creating something out of parts that would each be almost the maximum size of the build area. When assembled it would be very big. This might require an enclosure around the Reprap in order to prevent warping and definitely needs a heated bed before I would even consider it.

  7. Model car. I would like to produce something to show my friends at Jagnuts, the car club that I belong to. I was thinking of creating a scale model e-type Jag. There are a number of 3d models of them available that I could use as a starting point. I would print it as several parts that could be painted and then assembled.

  8. HO scale buildings for my model railroad. I think that creating one-off plastic items for hobbies is one of the best uses for these machines. I can create flat wall and roof sections, doors, windows, chimneys, steps and a host of other parts that can be assembled later into buildings that are unique to my layout or even copy buildings in my city. It will depend on how much post-printing cleanup and sanding is required to produce a good looking final product.

  9. Organette or busker organ. This would be a big project and would require some significant design work prior to building anything. I have long been a fan of mechanical music machines, the ones that play a punched paper roll. They disappeared in the early part of the last century when the gramophone rendered them obsolete but they are fascinating machines and there are hundreds of different types. I have plans for a number of machines ranging from a small “monkey organ” to a large Wurlitzer band organ that I could use as a starting point. It would be nice to create something that actually plays music and then turn the plans loose on Thingiverse.

    Related projects - These do not necessarily require the Mendel to build, but they provide additional capabilities to the workshop

  1. Enclosure – A simple enclosed box for the Mendel allows for containment of toxic fumes (they would be vented outdoors) as well as maintaining a heated environment to prevent warping of larger pieces. This is one of the simplest additions to build and might be one of the first projects that I undertake, just for the sake of my health.

  2. Heated build platform – This is also a high priority project. Heated platforms help to prevent warping of parts. They greatly increase build quality and reduce waste due to scrapped parts. I have already ordered the heater pad, thermistor and PID controller for this project. I will use a flat aluminium plate for the bed which I will source locally.

  3. 3D Scanner. An excellent, self contained, laser scanner using laser pointers was described in Make Magazine. Everyone with a Reprap should have some kind of 3d scanner to allow them to create 3d models of existing items without having to manually model them from scratch.

  4. Powder printer - Mentioned above. I think that this machine will provide an excellent complement to the capabilities of the Mendel. It can be used to create parts in clay, ceramic, glass, plaster and some other materials. My reading indicates that the DIY versions lack the precision of the Mendel but the powder bed provides support for overhangs which allows production of parts that are currently impossible on the Reprap. With an 8.5” X 14” build area and at least 12” to 14" depth in the build bin it can also create parts that are much larger than the current Mendel build area.

  5. Kiln – A lot of the materials used by the powder printer require firing before they can be used. This applies especially to the Clay and Glass materials. There are a number of sets of open source plans out there in Internet Land so it would be a case of picking one and building it.

These are only a few ideas off the top of my head. The more I think the more stuff comes to mind. It is going to be a very interesting year.

Wednesday, February 2, 2011

Close to The Finish Line!

I have been making progress but not as fast as I would like. It seems that I can only squeeze a half hour at a time to work on the Mendel so everything just creeps along. At least it is still moving forward and no new problems have arisen.

I have managed to fabricate an electronics mount out of fibreboard and mounted it to the machine. Sorry for the fuzzy picture. All of the boards are installed and I have made up all three cables for the stepper driver boards. One advantage of this side mount design is that the cables are much shorter. I hope to get the rest of the wiring done tonight so I can see at least one of the axis move under it's own power. Very exiting.

I made a small mount for the 12v power socket out of a small bit of U shaped aluminum extrusion. It works fine and is very solid. I plan on mounting the USB board on top of it with a piece of double sided foam tape so that problem is also solved.

I have fabricated new opto flags out of heavier aluminum from my scrap box and my new Z-axis belt arrived. It fit perfectly and is now installed so I have all three axis moving OK by hand. I also installed the bed so the mechanical build is complete. As a side note, my friend Mike from Method to his Madness suggested simply doubling up the layers of pop can aluminum to get the needed stiffness for the flags. I never seem to think of these simple solutions to my problems so it is always good to have another set of eyes looking at things.

Mike and I have been discussing getting a set of Mendel parts printed for him when I get this thing operational. I have a roll of PLA so I could even print the bushings for a Prussa. We'll have to see how long it takes to get the calibration right but it would definitely be in my interest to have another working printer in the neighborhood in case of problems.

I am already compiling a list of things that I want to try once I get it running. I will write up a post on various projects I am considering so I can get some feedback.

Thursday, January 27, 2011

A Little Progress

I have spent most of this week working on costuming for my daughter's musical theatre project so I haven't managed to get much done on the Mendel. However, I did manage to make a flowing black robe and a Greek helmet with a silk flame built into the top so she could play Hades in a musical number from Hercules so the week wasn't a total loss. Whenever I am faced with something like this I immediately turn to the Instructables website. I was able to find instructions for a cardboard version of a Roman helmet that worked great. This is one of the best sites on the Net for information on creative projects.

I did manage to find time to add a washer to all of my idler bearings for the belts. This provides just enough extra space so the belts move smoothly. The X and Y carriages both move smoothly now.

I have also roughed out the mounting board for my electronics. I will cut it and drill the holes tomorrow. I am planning on using the printed mountings for the original laser cut mounting boards to mount it so it should be a nice clean job.

A couple of other small jobs that I will get done in the next day or so:
  • make a new set of opto flags. The pop can aluminum I used for the original ones is just too light. They flex in a strong breeze.
  • make a mounting bracket for the 12v power connector. just need to bend and drill a piece of aluminum
  • make some sort of mount for the USB board. No mounting holes in it so I'm not sure what I will do there.
After I wire up the electronics I will finish off the extruder. I started to assemble it a while back but never finished. I stopped at the point where I was going to make the heater coil. When I read the instructions I realized that they wanted me to turn on the heater in order to cure the paste that holds the wire in place so I had to wait until I had the electronics ready.

My new Z-axis belt has been shipped and should be here within the week. Things are looking good!

Monday, January 24, 2011

Some Progress and Some Planning

Well, I pretty much completed the mechanical construction this weekend. I installed the Y-axis bars and the chassis. I had to remove and rebuild all the bearings on the chassis in order to get them to slide smoothly on the bars but I managed it eventually. Only the installation of the bed remains and I may wait until the heater arrives and make an aluminum bed instead of the laser cut acrylic that I have now.

I discovered one more problem with the mechanicals that I will have to fix. The idler bearings for the belts don't have quite enough room for my 1/4" belts. The belts stay on but they rub against the fender washers and the friction will be a problem during operation. I will have to remove all of them and add another washer or two to make a bit more room for the belt. Not difficult, just one more small tuning type task.

I also ordered a new z-axis belt from SDP-SI. I was able to order the same belt that I had before but with an extra two inches of length (39" vs 37").

Next up - the Electronics!

The next step is the installation of the electronics. I have the Gen-3 remix from Techzone and the boards are considerably smaller than the original boards for which the laser cut mounting boards were designed. I discovered a great alternate design on the Techzone Gen-3 Installation Wiki page that mounts on the side of the Mendel and supports all the boards on a single panel:

Single board electronics mount.

Side mounting of the board with zip ties.

This one is made out of a used nylon cutting board but I think that I can find a scrap of something around the garage to use.

Note - there are actually two Wiki pages for installing the Techzone electronics. The one with this nice mount is largely incomplete. I think that they abandoned it and started over. The one that contains the most current and complete information on installation can be found here.

On the Wiki they also discuss the possibility of using an additional stepper driver board for the extruder rather than using the extruder board to drive it. Apparently it results in a more reliable and quiet extruder. I will have to look into this. Perhaps I can find some information on the forums from someone who has tried it.

I admit to being intimidated by the prospect of installing the boards and wiring everything up. When doing the mechanical build I was able to disassemble and fix anything that I messed up. With circuits I may not know until I turn on the power that I have an issue and it may be too late at that point to avoid the smoke and sparks. I will just have to proceed carefully and do any testing with only the minimum number of boards connected in order to limit any damage that might occur. In a worst case I can always buy replacement boards from Techzone but I would like to avoid spending too much more on the machine.

Wednesday, January 19, 2011

Problem Solved! .......... And a new problem arises

I added the stick-on rubber feet to the Mendel and they raised it just high enough for the Z-screws to clear the bench. I also found that using lock washers on each side of the Z-axis bearings solved my problem with the washers contacting the mounting screws. This means that I am good to go for the rest of the build.

Or it would if I hadn't encouontered another problem as soon as I moved on. The Z-axis belt proved to be too short, even with the tensioner in the loosest position (as these pictures show. I obviously messed up my parts order somehow so I will take a look at the bill of sale to see where I went wrong.

This doesn't mean that I am stalled again. I should be able to proceed with everything else while waiting for the new belt to arrive. I now have all the motors installed and I have the x-axis moving smoothly (by hand). I think that the next step is to install the electronics and the build table.

Wednesday, January 12, 2011

X-Carriage Rebuild

A correction of my last post. The part that I broke was not part of the extruder. It was actually the lower X-carriage. See Below:

When the upper and lower parts of the carriage were assembled the 2 sets of 180 bearings did not close on the steel rod. When I tightened the bolts on that side the two parts of the carriage were drawn together and the lower one snapped. You can see the stress marks where it broke.

When I took it apart tonight I found that it had also broken at the belt clamp mount.

I carefully measured everything that I could think of to compare the original parts that I got from Nophead against the new ones but they seem to be identical. I can only assume that I did something incorrectly during the assembly that threw off the fit but I had completely disassembled it by the time I realized this so I will probably never know. At least I can confirm that Nophead's parts were not the cause of the problem. That comes as no surprise since they have been excellent in fit and quality throughout the build while my own skills have proved to be .............. slightly less than excellent, shall we say?

It only took a half hour to take it all apart and reassemble it. It now fits fine, moves smoothly and I can proceed to fixing my problems with the Z-axis.

I picked up some rubber feet for the bottom of the machine today. They should lift it up enough to resolve my problem with the Z screws contacting the bench and also will help with vibrations. I still have to figure out how to assemble it so that the screws move smoothly. currently the bearings are being contacted by something and won't rotate.

Thursday, January 6, 2011

I'm not Dead!

I'm back!

I never expected when I paused for my vacation back in July that I would still be paused at the end of December. Some health problems combined with an extremely busy fall/winter have kept me away from the workshop for far too long. I notice that I am not the only one as the frequency of posts from all the blogs that I follow has fallen off considerably over the last 6 months.

I went downstairs yesterday and tidied up the workbench so I can start working on the Mendel again. Just to recap - I have finished the basic mechanical structure and I am working on the z axis mechanism. I had to get a new set of extruder parts since I clumsily broke the ones that Nophead made for me by overtightening the bolts. The new parts arrived long ago and need to be assembled. This will be the third time since I had to toss the first set of cast parts that I bought due to their poor quality.

My current problem is that the washers that sandwich the bearings for the Z-axis rods are not the right size. They are too large and interfere with the operation of the bearings. I haven't been able to find the correct washers anywhere here so I have used my bench grinder to modify the ones that I have. Hopefully that will take care of things and I can get moving again.

Also, the z-axis rods extend too far below the chassis. I think this is due to the 1/4" nuts being too large. I will have to put some rubber feet on the Mendel to prevent the rods from contacting the bench.

Hopefully, I will have more progress to report later this week.