Monday, October 15, 2012

New Power Supply

Someone had a question about my power supply so I thought I would post a pic.  It hasn't arrived yet and it has been 4 weeks.  I usually receive items sent with USPS within 3 weeks so if I don't get it in the next few days I will have to start tracking it down (bummer).  In any case, this is what I am waiting for:

These have become quite popular for Repraps.  They are small (only about 8x10 inches) yet provide enough current to support dual extruders and a heated bed.  My whole rig should only draw about 16 amps when everything is running so this has lots of extra capacity.  You have to add a power cord and a switch but that is fairly straightforward.  There is also a switch on them to change between 120v and 220v so they can be used anywhere.

Thingiverse has a couple of printable end-caps for these that help to clean up the looks and cover the exposed terminals.  I would like to design and print a case that will contain the power supply, the Ramps boards and the LCD Controller panel.  This would either sit beside the printer or mount to the side of it (for portability). 

I tried to install the QU BD extruders on my X-carriage this weekend but ran into a couple of problems.  The first one was that the extruder barrel is quite short.  It would not reach beyond the bottom of the X-carriage until I removed the carriage and cut off the tabs that held bolts for tightening the bearing clamps.  Actually the bolts don't seem to be necessary as the clamps hold the bearings tightly enough without them.  The second issue is that the extruder motor (I am only installing one to start with) hits the belt clamps when I try to install it.  I may have to come up with some modification to the belt clamps to get this to work but it shouldn't be too difficult.  I may be able to just flip the clamps to the bottom of the carriage instead of the top.

Thursday, October 11, 2012

Extruders Have Arrived

The QU BD dual extruder setup arrived last night.   Yay!

Everything was very well packaged and organized and I was able to completely assemble both extruders in about 30 minutes while sitting in front of the TV.   One of the nuts seems to have a bad set of threads so I couldn't attach them to the mounting plate. It kept jamming on the heater barrel and I was not willing to force it.  I will run a tap through it tonight and finish the assembly.  My wife and daughter are both sick so I had other priorities last night.

The plate fits on my X-carriage just fine but I am not sure yet whether I can fit both extruders down through the hole in the carriage.  If not I will have to assemble it as a single extruder and then design and print a new carriage when it is up and running.

The only component I am waiting for now is the power supply.  I can always use the workstation power supply that I bought for my last machine until it arrives but the new one is much smaller and neater.  It will make for a much better organized machine if I can combine the power supply and all the electronics into a single case.

Tuesday, October 9, 2012

A Few Pictures

Here are a few pictures of my current hardware projects

 Here is the exploded extruder from my Classic Mendel.  I believe that the connection between the PTFE and the printed parts failed, allowing the melted plastic to leak out and force the whole nozzle crooked.  I am hoping for better luck with my new dual extruders from QU-BD but time will tell. On the upside, I have the printed parts for 3 extruders and could easily just buy hot ends and assemble them all if needed.

 This is the gantry for my DIYLILCNC.  There are still a lot of parts to go on it but the assembly seems to be fairly straightforward.  It is mostly just a matter of finding the time.

Here is the current Prusa Mendel under construction. It has been much easier to build.  the belt clamps for the Y axis don't match the holes on my sheet piece but that is what I get for buying from multiple different suppliers.  I will just make a couple by hand from some scrap aluminum.  Also, I bought a set of cables but they turned out to have female connectors on both ends and I can't seem to find a male connector locally so I will have to use a small piece of perf board and some pins.  Still, not a big deal compared to my issues with the last machine.

Friday, October 5, 2012

A Return to Posting

I have decided to start posting on this blog again.  I doubt that there are many folks out there who are waiting breathlessly for information on what I am doing but this was always intended to just be a record of my progress for my own use.

Things have actually progressed here even though I have not documented them.  After the extruder "blowed up" on my classic Mendel I decided to build a Prusa rather than repair the old one.  It has turned out to be a great decision.  The build went quickly (for me anyway) and I am just waiting for the dual extruders to arrive before firing it up. 

Some specs on the new machine:

  • Prusa Mendel (parts bought on Ebay)
  • Ramps electronics (came with a full wiring set for a Prusa)
  • Full hardware set bought online
  • LM8UU Linear bearings
  • LCD screen extension for Ramps
  • Dual QU BD universal extruders (1.75mm)
  • PCB heated bed kit
I financed QU-BD on Kickstarter so I have had to wait a while for them to get their first shipments out.  It took a couple of months for me to build the Mendel anyway and they have just announced that they have shipped all of their Kickstarter related hardware to their backers so I am hoping that the extruders will be here within the next few days.  I have both ABS and PLA filament in the 1.75mm size so I will probably set up the extruders by material rather than with various colors.

I also bought a small power supply on Ebay.  This is one of the ones intended for automotive lighting systems.  They are becoming very popular for Repraps as they are smaller than the older PC power supplies like the one I used on my last machine.  I plan on printing a case  that can combine the ramps, the power supply and the LCD screen into a single compact unit along with a cooling fan.

Construction on my DIYLILCNC is also progressing.  The main parts of the gantry have been assembled and the parts for the bed have been cut.  All of the mechanical and electronic parts are here, I just need to get the time to complete assembly.  It will be great to have something that can cut sheet parts for projects as a complement to the plastic parts created by the Mendel.  Note that the design for the 2.0 version is now out so I am, once again, constructing a machine that is one version behind the rest of the world.

Friday, April 13, 2012

Much Progress, Some Issues.

It has been a while since I posted, mostly because I have been meaning to take some pictures of various things to show what I have been doing.  Since I still haven't taken those photos I decided to just go ahead and post an update anyway.  Maybe I can get the pictures taken this weekend.

Things were going fairly well for a while.  I finished making a circuit board clamp that I found on Thingiverse and it works fine (my first multi-part object).  In the process I used up the last of my grey PLA and switched to the 5lb roll of Green that I had purchased.  I found that the green filament melted at a lower temp and would turn black occasionally at the temps I was using previously.  After some experimentation I found that printing at a set temp of 187 worked fine but I still have to do some tests on the actual vs reported temp to see whether it is reporting accurately.  Also, it appears that all PLA is not created equal and I may have to make adjustments every time I change a roll.

I removed the spool from my electrical cord reel, sawed it in half, and dropped my green filament in.  I managed to remove the winding handle without breaking it so I can use it to lock the halves of the spool together whenever I drop a new roll of filament in.  I had tried to print a Thingiverse object that was intended for that purpose but found an interesting issue instead:  The large body of the plug printed fine but the fill (set at 60%) began to sag in the middle so that after about 2" of height there was a dip of about 2mm in the center of the object and when the extruder attempted to print the prongs in that spot it was too high above the existing layer to bond.  I believe this is caused by the plastic being too soft and spreading out too much horizontally after it is laid down.

I also started to encounter some missing steps in my prints.  Since my first prints did not encounter this I know that it is not caused by electronics or firmware.  It is happening consistently now but only in one direction on the X-axis, so my prints slowly lean over as successive layers are laid down.  I have increased the current to the X-axis as well as adding heat sinks to all my stepper controllers (in case I need to increase current to others).  I also loosened up the bolts holding the X-axis bearings.  They were quite tight when I checked them so they may be my problem if they were restricting the bearings rotation.

My biggest problem is that I have large blobs of plastic oozing out of the extruder somewhere hidden by the X-carriage.  It started slowly but got progressively worse over time.  I am sure that the original problem was caused by an extruder crash into the print bed.  Since I did not have my endstops working I was manually zeroing the print head and then removing the home instruction from the G-code.  Of course, the inevitable happened and I forgot to remove the instruction once.  That resulted in a full speed crash on all the axis.  I wanted to print instead of taking the time to resolve the endstop issue and so I must pay for my impatience.

So, before I try printing again to see if my adjustments to the x-axis solve the missing steps problem I am removing the extruder to rebuild it.  I have additional brass tips, PEEK sleeves and a couple of removable heaters from Techzone that I never used so I should be able to get it back in service fairly quickly.  At the same time I will install microswitches to replace the opto-endstops that I have never managed to get working.  I tested the mechanical switches with the sanguinololu and they worked fine so I just need to remove the optos and get them mounted.

Hopefully these changes will give me a stable platform so I can proceed with some of the backlog of print objects that I want to produce.  At the very least I can say that I am having a great time after such a long time building the machine itself.  Fine tuning and repairing are a lot more fun.

And I promise, pictures soon!

Wednesday, March 14, 2012

First Printed Object!!

Huzzah!  After two years of muddling about I have managed to coax my Mendel into actually printing something.  And it turns out that I didn't even need a new main board!

I had noticed that the electronics would work for about 20 seconds before shutting down so I knew that the problem was not in the stepper controllers but it seemed to me that overheating could be causing a shutdown.  Then, when things had cooled down, it could be made to work again.  I reasoned that perhaps I had the current set too high on the steppers so I turned them all down and tried it again.  Lo and behold everything began working correctly so I proceeded to try printing some small parts.

I managed to get some small things to print correctly, if a little sloppily, so I decided to go for it and try to print a shot glass for the traditional toast to a new machine.  The results (.4mm layers, 200C, 50% infill and no heated bed) are below:

In the picture it appears to narrow towards the bottom but that is caused by the camera angle.  It actually came out great.  There are quite a few blobs but I will experiment with the settings to resolve that.  I suppose it is either too hot or the print head was moving too slowly.   In any case, it is water tight and shaped like it is supposed to be shaped.

I still don't have my endstops working, which means that I have to set everything up manually.  I have been editing the Gcode to remove the homing instructions before and after the print.  The most difficult part is setting the position of the Z axis prior to starting.  Since I am doing it by eye it is hard to get the height set consistently and I have had to stop several prints because I started them with the print head set too high.I could make a spacer to set the height but I think fixing the endstops is a better use of my time.

I have gone through the few feet of grey PLA that I had and I will be starting into my 5lb lot of green PLA so I went to Lowes and bought an electrical cord reel to wind it on.  

Quite a few people are using these now.  They are cheap and sturdy.  the only problem is that the reel is not split in the middle.  that means that I have to wind the whole lot of filament onto it by hand instead of splitting the reel and just dropping the roll in.  There are a number of mods for this reel on Thingiverse including a spindle for 5lb spools and some connectors that allow you to modify it so that the reels can be removed and changed.  I believe that I also came across an actual printable reel designed for these but I have to go find it again.

I have a few items that I want to get printed now that I have it working.  The highest priority, now that summer is coming again, is an  adapter to mount a set of relays under the hood of my Jaguar XJS.  I installed electric fans last year and the relays that came with them do not fit on the mounting bar of the car.  I will have to print those from ABS since it gets pretty hot under there when running the V12 in the summer heat.  I think it may get above the melting point for PLA.

I also want to print a set of clips to reinstall a piece of glass in our stereo cabinet.  None of the mirror or glass mounting clips available locally will fit this oddball installation.  The best thing about this one is that I get to show my wife how useful a Reprap can be!

Thursday, March 8, 2012

A satellite of your very own!

I am still waiting for my replacement Sanguinololu but here is a really interesting story to help pass the time:

The folks at Evadot have designed a board to be the brains of your very own satellite.  A CubeSat is a low cost micro-satellite platform that universities and others have been using for a while.  Of course, "low cost" is relative.  A basic CubeSat kit costs anywhere from 7,000 - $10,000 and the launch costs are another $40,000 at the moment.  On top of that you would have to add your own sensors, etc. for whatever mission you have in mind.  Evadot wants to open things up a bit by offering a much cheaper alternative to the present CubeSat kits on the market.

Give the article a read and keep an eye on these folks.  These boards can also be used for a variety of other cool hackerish purposes, including robotics.  Keep in mind however, that launch costs are dropping and you might actually be able to afford to launch your own satellite in a few years.

Tuesday, February 21, 2012

Success and Disaster!

I have been unable to resolve my endstop issue so I will probably remove them and go to the limit switches which I have already tested and found to work fine.  In the meantime I decided to go ahead and test the machine without them by manually setting the home position and editing the G-code to remove the homing instructions.

Success - I managed to print a part on my second try.  The first time I set the extruder position too high and it simply sprayed the filament into a big pile even though it was moving correctly in the X and Y.  I still had it positioned about one millimeter too high on my second try but it created the outer shell of the part correctly.  The infill did not fare so well.  Since there were many quick movements and changes of direction the  filament did not have time to drop into position before the hot end moved. and the holes in the part were blocked by a mass of filament caused by the suspended thread being dragged over the hole before it dropped into place.  They could be drilled out however so I am counting it as a success.  Very big day and I was extremely happy.

Then the Gremlins arrived.  When I adjusted the height again and started the third print it stopped dead in the middle of the first layer.  I found that the green LED was no longer lit on the Sanguinololu and I got a message on the workstation: "USB port has exceeded voltage limits".  Now everything is dead so I believe that something has been blown on the main board.  Whenever I plug in the USB I get the "Exceeded Voltage" message and nothing happens.  Maybe a short?  One other disturbing symptom - When I power up the 12v supply the mosfet down by the thermistor connectors becomes immediately hot enough to burn my finger, and I mean immediately, like from cool to burning in less than a second!

So I may have a trashed main board.  Need to do some more troubleshooting but I am too depressed right now.  At least I actually printed something so that is progress.

Wednesday, February 1, 2012

Hardware Complete!

This is a real milestone for me.  I believe that all the hardware is finally working properly so I only have a couple of software issues to resolve. 

I replaced the endstops last night with a set of spares that I had bought with the original Techzone electronics.  I always figured that I would burn out one or two and they were cheap so I bought a full set of replacements.  These are slightly different from the ones I am replacing.  They have LED's on them so I can see that they are getting power and are working properly.

Unfortunately they don't seem to be doing anything.  It makes no difference whether the optical signal is interrupted or not.  I can jog all three axis in both directions even with a card inserted in the endstop.  I think that this is an issue in the setup in Sprinter so I am going to look through the configuration code today.

I also need to reinstall Pronterface since it won't load an STL file.  This shouldn't be a big deal since I have confirmed that my other computer, on which I also installed Pronterface, can load them just fine.  I probably messed up the install of one of the several apps that Pronterface depends on so I will clean it all out and start the install from scratch.

As a final note I should mention that I started working with Sketchup 8 this week.  I downloaded a free addon that allows import and export of STL files and I have been able to create a couple of fairly simple part files for items that I would like to print.  I found it simple to learn and easy to use.

Monday, January 30, 2012

Endstop Issues and CNC Router Progress

I finally received my new stepper controllers from Pololu.  I put one together and slapped it in the extruder slot on the Sanguinololu and it promptly burned out.  That makes 4 controllers that have burned out, all when installed as the extruder controller.  Since I had it working once with the original controllers I moved one of them to the extruder and replaced it with the remaining new one.  Success!  I finally have all 3 axis as well as the extruder working properly.  I don't have any more spare Stepsticks so I am going to order a couple more since I still don't know why they have been burning out.

I still have a couple of small issues to deal with.  One of my endstops has burned out during all the messing around with the boards.  I have spares but I also have to make up some new cables since the new board sits in a different spot on the machine and the old ones aren't long enough to reach it.  I have also sprayed lithium grease into another of the endstops by accident so it registers as closed all the time.  I think a Q-tip and some rubbing alchohol should sort it out.

I also have a more serious and confusing issue to resolve.  I tried to load an STL file into Pronterface but I got an error.  It apparently couldn't find one of the Skeinforge modules.  I know that a new version of pronterface has come out since I loaded mine so I will try updating the whole thing and see if that makes any difference.   My installation of pronterface has been working fine for controlling the Mendel so I don't know exactly why there is an issue with the STL files but I am much more comfortable with software than hardware so I am sure that I can resolve it.

I have also been collecting all the bits and bobs needed to complete my DIYLILCNC router.  I had the laser cut pieces made up in September and bought the electronics at the same time.  Over the last couple of weeks I have purchased the bearings, belts, gears, motor shaft couplers, Acme rod, nuts and flanges and all the nuts/bolts/washers for assembly.  I still have to pick up the steel rod, square aluminum tubing and threaded rod but I can source them locally.  I also need to buy the correct Dremel tool to fit the carriage design.  Basically, I am ready to begin assembly.  The first step will be to prime and paint all of the MDF laser cut parts

One final bit of news.  I finally bit the bullet and bought a power supply on Ebay.  It is 30V, 5A so it should be good for anything that I am likely to want to do with it in the near future.  It should be here next week

USA Brand Precision Lab GQ-A305D Variable 30V 5A DC Power Supply s/CV & CC mode

Monday, January 23, 2012

I am still waiting on new Stepsticks (the first ones that I ordered couldn't handle 1/16th stepping) so I thought that I would do a short report on one of the nicest machines that I have seen for a while.  There have been a number of new printers that have appeared over the last few months but this one uses a unique open-source linear bearing system and is a truly elegant design.

It is called the Quantum ORD Bot and was created by Barton Dring who also created and sells the Makerslide linear bearings.  First, here's some info the bearing system:

Makerslide Rail
The system is basically a 20mm x 40mm aluminum extrusion along with a set of  parts designed to work with it.  Any parts that fit standard 20mm extrusions can be used and, in addition, Dring sells V-notched wheels that run along a pair of V rails integrated into the extrusion.  The wheels are designed to accept standard 5mmx16mmx5mm bearings as hubs which are simply press fit to install, and various spacers are available to mount them to flat stock. 

Makerslide standard carriage with wheels mounted

V-wheels with standard 16mm skate bearings
The Makerslide store sells a set of standardized parts like the carriage that can be integrated into your designs or you can buy the wheels and mount them to your own carriage.  The parts can be ordered at the Makerslide Store and he will even cut it to your order prior to shipping.

The whole purpose behind this is........ well, I'll let Barton explain it himself:

"The biggest design, cost and fabrication hurdles in a new CNC design are the linear bearings. There are a lot of commercial and DIY solutions out there, but none support an easy, low cost and rapid fabrication philosophy. I want to create a solution to this. The idea is to use a method that seamlessly integrates into standard aluminum extrusion systems. 

The basic bearing concept is not new. I have used it for years in my own designs and many high end commercial systems use it. It is the V wheel running on V rail. The problem with the commercial systems is that they are expensive, require a lot of accurate fabrication to integrate and don't seamlessly integrate into standard extrusion systems. 

MakerSlide is a V rail integrated into a standard extrusion profile. Since it is based on a standard profile from several sources."

He financed the project through Kickstarter.  The parts are inexpensive and the cost of the rail is currently set at 1 cent/mm (or about $3.00/foot).  That is an incredible bargain in the world of precise linear control.   Makers with a supply of Makerslide rails and parts on hand could prototype their designs extremely quickly

Of course the next thing the world needed was a 3d printer designed around the Makerslide components and Mr. Dring took care of that as well.  Behold, the Quantum ORD Bot!

Quantum ORD Bot

It's a nice little 3d printer that uses the Makerslide as both structure and linear bearing system in all three dimensions.  The usual rat's nest of wires is run inside the extrusions so it has a very clean look to it.  Information on this machine can be found on Thingiverse or on his Buildlog blog posting.  The prototype has a small build area but it has already undergone a redesign to address that issue.

The best thing about this is that the parts can all be purchased for a very reasonable cost.  The worst thing about it is that there is increasing demand for the Makerslide extrusion as word spreads so it sells out very quickly every time a batch arrives at the store.  Still, this is a clean, elegant machine with a very stiff chassis.  It might be worthwhile taking a look at it if you haven't settled on a design yet for your next project.

Wednesday, January 4, 2012

Some Progress, Still Waiting

I am still waiting for my new pololu boards to arrive but I have managed to make some progress in the meantime. 

It was immediately apparent that my axis were not moving as they should.  The steps/mm were obviously incorrect but it took me a while to figure out what they should be.  I could see that the X and Y were moving in tiny increments and finally realized that I had to multiply by 16 to allow for the microstepping (Duh!).  That worked but then their movement seemed to swing too far in the other direction.  Luckily I found Josef Prusa's online RepRap Calculator (Calculator).  Once I had carefully entered the correct data (gear tooth counts, microstepping settings belt pitch angle, step angles and leadscrew pitch) it spit out settings that seem to be correct for my machine.

I think that the extruder setting is still off.   It seems to be pushing out more than 5mm of extrusion when I hit the jog button but I will wait until I have all three axis working to mess with it further.

I am working on the heated bed while I wait.  I got the PID out and wired it up yesterday.  since it runs on 120v AC I don't want to use it without an enclosure but I will give it a quick power up to confirm that it is working.  I have attached the heater pad to my build plate but I didn't get the thermistor wired up last night.  I should be able to finish it up tonight and give it a try.  Assuming that it works I will finish the enclosure and get everything tidied up.

I expect that the new stepper drivers should be here within the week.  I have ordered some ABS to complement the PLA that I already have on hand so I will be able to experiment with the different materials.