Monday, July 26, 2010
Unfortunately I won't be leaping right back into the work on the Mendel. I have an old Jaguar that has been up on axle stands for the better part of a year for some engine work. The work isn't that complicated but I have been very lazy. The other guys in my car club are starting to wonder why I always show up to our get-togethers in a Toyota! I am going to focus on getting the car back on the road for the next week or so and hopefully I can then get back to the Reprap.
Wednesday, June 30, 2010
Tuesday, June 29, 2010
I finally have a few shots of my progress. I have completed the frame and installed the x-axis. My only problem is that the z-screws seem to project too far below the machine and raise it up off the feet. I haven't checked yet to see if I measured something wrong or if this is due to using nuts that are thicker than intended. I expect the fix to be fairly straightforward though.
Closeup of the z-axis 360 bearing and the x-axis motor.
The y-axis chassis is ready to go although I still have to do final adjustments on the bearings.
And, finally, a quick shot of the y-axis 360 bearings.
So, next steps are:
- Resolve the issue with the z-screws.
- Install the y-chassis and the bed.
- Install the belts.
- Move on to the electronics
I'm feeling pretty good at this point. the mechanical construction is almost complete. Since I bought pre-built electronics I am cautiously optimistic that they will work out of the box. That means that I could have a working Mendel within a week or so.
that is, if I can continue to work on it. Vacation is coming up and I need to put some serious time into getting my old '76 motorhome into shape for the trip. With a vehicle this old, that is only used once a year, there is always something to fix before we can head out so the Mendel may have to wait until we get back for the final touches.
I have ordered 5 lbs. of green PLA which should be here this week so I will be ready to build as soon as the machine is done. Then the real fun begins!
Tuesday, June 22, 2010
The open source powder printer chassis
Peter's geared drive mechanism for the bins
Monday, June 14, 2010
I am now installing the electronics on the two electronics boards and then it will be time to begin the final frame construction. Since the boards that I bought from Techzone are smaller than the original design I am trying to figure out exactly where they mount and how. I should have that straightened out today.
The main problem that I still have to face is that I have have not yet managed to get the gears off of my stepper motors. I tried to drive the motor shaft out with a punch but it seems to be very firmly attached to the shaft. Even a couple of shots with a 2 pound steel mallet didn't budge it. I have resorted to attempting to cut one of them off with the Dremel. I wasn't able to finish the job last night so I will be back at it tonight or tomorrow. if I can't get the gears off, or if I damage the shaft in the process, I will just have to order new motors. At least they are not one of the more costly parts.
BTW - Nophead, who made my plastic parts, posted an excellent article on his blog today regarding an enclosure for the entire Mendel. It basically acts like a heated chamber and can also be used to contain and control fumes. It looks like a good idea to me but I would probably mount the electronics outside the box. I worry that the heat inside might shorten their life.
Friday, June 11, 2010
It took me two weeks of spare time and hours of drilling, grinding and sanding to get all the subassemblies for the x-axis built using the cast parts. Even then, they didn't align properly when it came to installing them on the rails. With the properly printed parts I was able to build all of the same subassemblies in 2 hours and all of the holes for the rails align so they should go together just fine. I hope to have the whole x-axis together tonight if I get some free time. Since it has been raining here for days that seems likely.
Thursday, June 3, 2010
So, I will have to wait a week or so for them to arrive and then the build should proceed in a fairly straightforward manner.
In the meantime I will try to get the old gears off my motors and install the new ones. I can also finish the extruder build, except for the HeatCore piece.
Tuesday, June 1, 2010
Monday, April 26, 2010
I then started working on the assembly of the x axis and immediately had trouble. The biggest problem is that the holes for the bars do not line up correctly. from measuring the x axis carriage I can see that the bars need to be about 5cm apart. The spacing of the holes on the various parts varies from 4cm to 5.5cm. This means that I have to go back to my trusty Xacto knife and Dremel to adjust them. I hope to have the full x-axis assembly assembled tonight or tomorrow.
When attempting to install the first stepper motor I found that there was some kind of mount already installed on the motor with a pair of screws. These have proved to be extremely difficult to remove and I am afraid that they have permanent threadlock on them. I have tried a couple of things that have not worked and my next step may be to heat them up with my soldering iron in an attempt to defeat the threadlock. Hopefully I don't also defeat the motor itself!
There were several ebay auctions for full parts sets for a "Wade" style geared extruder. Given that the geared extruders have a better reputation for reliability, I decided to go to one of those right away. The extruder parts from the cast set are a bit rough anyway. I managed to win the auction and the parts should be here within a week or so since they are actually coming from Toronto, right here in Canada.
I should also comment on a post that I made a while back. I was going to order some of the trickier parts from Provantage to avoid having to adjust the cast ones. Although they were very helpful and prompt in their communications it turns out that Provantage does not ship to Canada (or anywhere internationally) unless you are buying the full set of Mendel parts ($1500!!!)
I guess I will continue with my "Hack it with sharp objects until it fits" method for the time being.
Monday, April 19, 2010
Powder printers, which lay down a thin layer of powder and then use a binder fluid to bond the object together, are now being built by the home hobbyist community. One of the factors limiting their usefulness is the powder being used as raw material.
Most commercial printers use proprietary materials in their print beds and they tend to be very expensive. Now that people are building their own machines there is a lot of interest in developing cheaper materials that can be created at home. There are a number of recipes for different powders out there for use in diy powder type printers. A lot of them, and the best of them, come from Open3dP (Open 3d Printing) at the university of Washington, though there are also a few others that I have seen on various forums.
I have collected as many of them as I have encountered in a single document which I am making available to anyone who might be interested. There is nothing revolutionary about this document. I will just save you the time of looking back through all the blog articles if you are trying to remember a formula. As time goes on I expect many people to be experimenting with different materials and I will update this document as I discover new information.
None of these recipes are my own. They are all the result of hard work done by other, smarter people so I can't answer any questions about them. Until I get a powder printer built I am not even able to try them myself. There is a lot of additional information available on the open3d site. That site is maintained by Professor Mark Gantor who has been very helpful in creating this document. Thanks to him especially for advising on how copyrights and proper credit should be handled. The Open3dP site should be the first stop for anyone experimenting with materials for powder printing.
For what it's worth, I offer this up to the powder printing community. The information is all in the public domain but the pictures are copyrighted by Professor Gantor. If you want to use the text in other documents please give proper credit to the original creators. The recipe book is in MS Word format and can be found here.
Two shots of the Idler Bracket
Vertical bearing 180 (very rough parts, will need major adjustment with sharp things)
When assembling the idler bracket I discovered that the 4mm fender washers that I bought are exactly the same diameter as the bearings so they will not work to constrain the x-axis belt. I went to Canadian Tire (my favorite store) and picked up a handful of 6mm fender washers which worked just fine. I also finally bought a set of metric hex wrenches to make assembly easier.
4mm washer on the right. Too small. Larger 6mm washer on the left. Just Right!
The opto flags need to be installed as you assemble the x-axis carriage and the vertical bearing so I will have to cut them out before proceeding further. I tried to print out the template last night but couldn't get the scale right. I will try again today and will probably use HeeksCad, which was conveniently blogged about by Niel Underwood over at RepRap Log Phase. It looks like it would be able to match the dimensions on the dxf file to the printer to get the scale right. We'll See. I did get a start on this task by buying a six pack of coke and drinking several, so can report that I have made progress.
Sam the Science Dog
Monday, April 12, 2010
On Saturday, I went out to the garage and cut all the smooth and threaded bar stock for the machine. It took about an hour and a half. I bought stainless for the smooth bars and I went through two hacksaw blades cutting it. I smoothed out the ends of those on the grinder and I was ready to go. I actually still have to go out and cut the three jigs because I forgot about them at the time but, I will cut them as I need them.
The molded set of RP parts I bought from Ireland are extremely rough. The holes are all undersized, probably due to shrinkage in the mold material, and have to be drilled out. If the shrinkage in the rubber caused undersized holes it also probably caused the entire part to be slightly oversized. Many of the holes were filled with a rubbery substance and others were completely filled in with the casting material. I finally realized that parts of the rubber mold had broken off in the bolt holes when the parts were removed from the mold. The missing holes are where the bits broke off in the previous casting and were not present during the molding of my parts. This would indicate that the quality of these cast parts drops significantly from the first casting onwards. There is also some warping but not enough to cause problems
Anyone buying these cast parts should inquire whether they came from the first or second casting from a particular set of molds. Anything after that is suspect. Whoever bought the set that was cast after mine probably had most of the holes completely filled. I would not recommend these cast parts unless you can acquire them for considerably less than a set of printed ones. They require much more manual cleanup to be usable.
I started by cleaning up and drilling out the parts for the carriage assembly. The x-carriage upper and lower parts have a lot of trapped nuts and some of them needed to be enlarged or cleaned up with a Dremmel in order to get the nuts into them. The majority of them were OK, however, and a bit of pressure with a set of pliers allowed me to force fit the nuts into their cavities.
Strangely enough, my most serious problem was that I don't have any metric hex wrenches. None of my SAE ones would fit well enough for even rough work. I had to grip the cap of the screw with a set of pliers since they require more torque than I was able to apply with fingers alone. I will pick up a set of metric hexes this week.
In the end, however, I was able to assemble the very first parts of my Mendel. I can see that the assembly will take quite a bit longer using these cast parts but they should all prove to be usable. I will certainly make printing a proper set of replacement parts a high priority as soon as the machine is operational though.
Wednesday, March 31, 2010
I attempted to order the drive gears and the x-carriage-lower_1off but their google widget told me that they didn't ship to Canada. An email to their contact address resulted in a very quick response from Nick Pace telling me that he would have it fixed in a day or so. I love good customer service!
This will probably drive the price of my Mendel up into "WTF territory" but I am past caring. I am having too much fun.
Friday, March 26, 2010
All my metric fasteners. Not too exciting in the boxes but you can't build a Mendel without em.
The X belt and 8 ft of additional belt for the Y and X axis.
4 NEMA17 stepper motors. I will have to remove the gears currently on the shafts since they do not fit my belts.
50 624 bearings and 2 608 bearings.
Various Printhead parts from Makergear, including their heater kit for the extruder. It allows me to make a heater that I can remove from the extruder if necessary to place on another one. Handy if the extruder fails, which seems to be quite common with us beginners.
The lasercut chassis, build plate and circuit board mounts. all ready to go.
Mendel vertices from James Villenieuve. I won't need these now since I will get another set along with my RP parts but I will keep them as spares and perhaps to kickstart the build of a second Mendel.
The power supply that came with my boards is a small 12v adapter. Probably fine for running the Reprap itself but I also want to run a heated build platform, cooling fans for pos-print cooldown and maybe some lighting. I found a 500W ATX power supply on Ebay for only $20 (plus another 20 for shipping of course) so I ordered it as well. Once I have it here I can decide how big a project box I need to contain everything.
Monday, March 22, 2010
Also, my electronics arrived today from TechZone Communications. Unfortunately I have to take care of some real priorities before I can get back to my hobbies. We have been waiting for almost a year to get my daughter in to see an orthopedic specialist about a knee injury and we finally have an appointment tomorrow morning. That means that we have to hit the highway to Saskatoon this afternoon. No time to look over the boards.
Last night I took pictures of all the parts that have arrived so far. When I get back I will post them and hopefully start setting up the electronics and motors on the workbench to try everything out. It will probably take 4 to 6 weeks for the printed parts to get here from the UK so I should have time to get bugs worked out of the electronics.
Friday, March 19, 2010
Jake Von Slatt's steampunk computer
This combination of mass produced industrial hardware and individual craftsmanship only lasted for a short time. Rising labour costs and the creation of the assembly line brought us to our modern world, where everything is affordable but nothing is unique.
So how does this relate to Rapid Prototyping? Well, we are now entering another era when individuals will be able to manufacture, in their own workshops, whatever they desire. These items will be as individual as their creators and, even if we all pass around the .STL files to make multiple copies, there is always an impulse to personalize “your” version of someone else’s design. A quick look at repstraps out there shows an amazing variety of designs, all reflecting their creator’s individual goals and design choices. They even have unique names, as was common for Victorian devices.
I have been wondering what a steampunk Mendel would look like. The rod used throughout would have to be brass, of course, as would all the connectors. The various plastic parts could probably be made out of wood but that really goes against the whole reprap philosophy. Perhaps black ABS with scrollwork grooves that could be later picked out with gold paint. Add a build surface of polished wood with a brass plate for the heater and you have a RepRap for Captain Nemo. Handy when you are on the bottom of the ocean without your full shipyard available and you need a replacement trigger for your electric rifle.
Nemo: "Drat, my electro-rifle is damaged. To the Mendel M. Aronnax!"
Perhaps the actual steampunk fad has just about run its’ course. Now that it seems to be everywhere on the internet, maybe folks will become bored with it. I hope not, I love the whole brass and wood look with the elegence that they imply. I am not enough of a sociologist to know for sure how long steampunk will last but I believe that the underlying philosophy that drives the design and creation of such unique hardware will continue to be apparent in the RepRap community for years to come
Thursday, March 18, 2010
Here's a closeup. the quality looks pretty good. Of course looks can be deceiving but I thought it was worth the risk so I threw in a bid just shy of $400.
They finally sold for $465 which is still a bit too rich for me. I am hoping the fact that they were cast rather than printed or machined means that the seller will be making more sets. This could finally start bringing the price down.
Hopefully whoever bought these will post something to let all of us potential buyers know what the quality is like.
Tuesday, March 16, 2010
It is fairly obvious that I will need to add a heated platform fairly soon after I complete the Mendel if I want it to actually be usable. I have investigated any number of designs on various blogs. Most of them look fairly simple but, being mechanicaly challenged, I want to take the absolute easiest path possible. I think that I have found that in Tim's design over at Bothacker.com. It is a bit more expensive than others I have seen but tons easier to implement. This guy is my hero, his repstrap design, using aluminum channel, is also extremely clean and elegant.
The following links and pictures have been shamelessy stolen from Tim's website.
The setup consists of the following:
- 4×4 flexible silicone rubber heater, 115VAC, with pressure sensitive adhesive on one side, ~$30
- Commercial PID temperature controller, $42
- Type-K thermocouple, ~$6
I find this approach attractive because it is basically a buy it and install it solution. The pads even come with their own adhesive already applied. He has also posted a couple of pics of his control box which is exactly what I was planning on setting up. It seems logical to have everything neatly enclosed in a project box and, in addition to the heater, there will probably be a number of additional systems to build and control as things progress. The workbench could become a mess of loose switches, wiring, etc. without some advance planning and organizing. Below are a couple of pics of Bothacker's control box which includes the bed heater controls, power supply, fans, control board, stepper drivers and an emergency cutoff switch. Very slick, and he still has lots of room on the front panel to add things.
These project boxes are not expensive. I have been looking as a couple on this site but I will wait until I have gathered all my electronics before ordering one to ensure that I get the right size.
As a final note - A new set of Mendel RP parts has shown up on Ebay so I threw a bid in on it. Given that the set sold by Adrian Bowyer went for $647 Canadian, I don't hold out much hope but you never know.
Monday, March 15, 2010
Friday, March 12, 2010
I have ordered all of the necessary parts except for the printed ones. Most of them have arrived and I expect to have the rest within the next week or so. I will post a cost breakdown of what I have purchased so far, where I obtained it and how much I paid. I have already found that I grossly overpaid for a few things that I could have found on Ebay or through the Reprap forums. Perhaps I can help someone else from making the same mistakes.
Of course, it is the replicated parts that are hardest to come by. I expect that the scarcity will resolve itself within the next 6 months or so since it creates a significant business opportunity for entrepreneur types. Anyone who is able to produce full sets of parts can essentially name their price at the moment. The set that Adrian Bowyer put up on Ebay about a week ago is currently listed at $427 (CAN) and hasn't yet arrived at the frantic bidding that always pushes things up a bit more in the last hour or so.
I have reached out to several of the user groups (without success so far) and I am also watching several sites that advertise the RP parts but are currently out of stock. I am still hopeful that I can find a set within the next few weeks.
If not I have plan B. Alvaro Fogassa documented the build of his 3d powder printer on his blog http://homemade3dprinter.blogspot.com/ and it looks like an excellent complement to the extrusion technology of the Repraps. I managed to find a printer identical to the one that he used on Ebay for $15 plus another $15 for shipping. I would prefer to build the Mendel first since it is better documented and I will have to do some design work on the powder printer but, if I become impatient, perhaps I will proceed with this project first.