MakerBot Build Log + Prop Control Discussion
Phil Pilgrim (PhiPi)
Posts: 23,514
The Thing-O-Matic kit arrived! Here's the open-box photo and a photo of its contents:
It was nicely packed, but the neat compartmentalization in smaller boxes hides one overwhelming realization: OMG! There are a lot of freaking parts in this kit! No wonder it took a month to ship. Just kitting the parts must take hours for each one. Well, it looks like building it will be a weeks-long not week-end project. I just hope I can keep the workspace organized that long.
Another first impression: The framework is bare plywood, which I knew from the product photos. It appears to be birch veneer over a single-ply core, probably of a softer wood. Given the necessary tolerances, I might have wished for 7-ply marine-grade plywood instead. So now I have to make a choice, since the Northwest is a damp climate: Varnish it? Head out to EdenSaw and find a marine-grade wood I can cut on my laser cutter? (I'm pretty sure the CAD files are available somewhere.) Or?
More to come -- slowly. I've still got the day job to think about.
-Phil
BTW, Rich (W9GFO) ordered his a little before I ordered mine and is probably a few steps ahead of me in the build process. So Rich, you're welcome to add your own impressions/experiences here if you like.
It was nicely packed, but the neat compartmentalization in smaller boxes hides one overwhelming realization: OMG! There are a lot of freaking parts in this kit! No wonder it took a month to ship. Just kitting the parts must take hours for each one. Well, it looks like building it will be a weeks-long not week-end project. I just hope I can keep the workspace organized that long.
Another first impression: The framework is bare plywood, which I knew from the product photos. It appears to be birch veneer over a single-ply core, probably of a softer wood. Given the necessary tolerances, I might have wished for 7-ply marine-grade plywood instead. So now I have to make a choice, since the Northwest is a damp climate: Varnish it? Head out to EdenSaw and find a marine-grade wood I can cut on my laser cutter? (I'm pretty sure the CAD files are available somewhere.) Or?
More to come -- slowly. I've still got the day job to think about.
-Phil
BTW, Rich (W9GFO) ordered his a little before I ordered mine and is probably a few steps ahead of me in the build process. So Rich, you're welcome to add your own impressions/experiences here if you like.
648 x 345 - 53K
648 x 486 - 46K
Comments
Thanks for sharing. I eagerly await futher updates.
Bean
I did order eMaker Huxley kit some weeks ago. I'm not sure when I'm supposed to get it, but hopefully within couple months. It's supposidely quite similar machine, but based on RepRap development and is made of printed plastic parts combined with metal rods.
My TOM is printing right now. I can offer some tips if you like... Ah what the heck here are the tips anyway.
Print out a new extruder! http://www.thingiverse.com/thing:7113 It will save much frustration with filament slipping and stepper skipping.
Modify the Z stage! The very short distance between the bearings on the Z stage is a bad design and will lead to problems. There are several mods for it on Thingiverse. I have designed a mod that requires zero additional hardware and is printed. It has been in use for a couple weeks and has worked flawlessly. I will be putting in on Thingiverse soon. If you like I can send you the files.
Print out some strain relief parts for the HBP (you are going to use the HBP and not the ABP right?) and the X axis endstop - another thing that I will be putting on Thingiverse but easy to design your own.
Get the aluminum plate to put on the HBP and a roll of the wide kapton tape. It makes raftless printing a piece of cake.
There are errors in the documentation. Be sure to read ahead - there are cases where if you were to follow step by step you might wish that you hadn't.
If you use a Mac,download Pleasant3D. Very useful program to view the toolpaths before printing.
If you use Sketchup, you'll need a plugin to export to stl. Also, do not design in mm inside Sketchup. Use inches instead. I have modified a plugin (it was super easy) to make exporting in the correct units a one step process. The reason is that for very small parts Sketchup may not work correctly.
Come to StudentRND on Sat Jul 23 where I will be presenting "Intro to 3D printing". It is free.
Rich H
Rich H
-Phil
Rich H
That looks more like a couple vacation days to me! Christmas came early for you sir. That sure looks like a fun project! I'm looking forward to pictures of the build.
Robert
Rich, did you varnish or paint your wood parts before assembling?
-Phil
Rich H
It might do to your Thing-O-Matic what it did to my shoes.
I've come to a decision on the plywood: I'm going to use it as-is. The okuma doesn't have as nice a surface finish as the birch laminate. Also, I don't have a spray setup where I can coat both sides of the pieces at once. I learned from experience over Christmas that coating one side (at a time) will cause thin plywood to warp as the varnish dries, so that's not an option. Plus, I share Rich''s concern about the tabs fitting the slots once the pieces are varnished. If the top piece wants to sag from the weight, I can always laser cut some struts to reinforce it.
-Phil
Today, I'm going to take Rich's advice and read through all the instructions before starting assembly.
-Phil
What a cool toy! (Yes, I know it's a serious piece of equipment, but... what a cool toy!!! :-> )
Getting the nuts into the T-slots and stationary long enough to start the screws can be frustrating. If you have children, their small fingers would definitely be an asset for this task. Barring the availability of forced child labor, an extensive swear vocabulary is the next best option. At least that has helped me.
Because the wood pieces are laser-cut, there's a balck ash that coats all the edges. The instructions recommend wiping it off with a damp paper towel. Well, that was a mess, with little paper shreds everywhere. I ended up using a damp microfiber rag instead. I still didn't get all of it off, though, to which my dirty smudges on the bare wood stand in mute testimony.
Be sure to pay close attention to the photos in the instructions when putting parts together. Because the tab and slot locations are symmetrical, it's very easy to attach parts backwards. Had the tab and slot locations been asymmetrical, this problem could have been alleviated.
The first order of business is to solder a cable to the belt drive motor and a connector to the end. What the instructions don't say is that the cable is much longer than it needs to be. Although the excess can be coiled under the front panel, cutting it shorter would have been the neater solution.
One of the next things the instructions have you do is sand one of the slots that the belt goes through a little deeper:
I used a file instead because it produced a neater recess than I could ever hope to get with sandpaper. Temporarily bolting the pieces together helped to get the file aligned properly. I assume that subsequent laser-cut fabs of these pieces will include the additional slot depth.
The belt rollers consist of rubber tubing pushed onto steel rods. You have to cut the tubing to length, and the instructions explicitly state that accuracy is important. What they don't explain is that it's almost impossible to trim a little of the end and have it come out square and smooth, if you cut it too long. My solution was to insert a bamboo barbecue skewer into the end to support the rubber, so I could cut around it with the provided razor blade. The results aren't perfect, but they're good enough.
The belt slides over the top of the heated build platform. One of the screws that holds the platform down to the frame also holds a silicone "nozzle wiper." If screwed down per the instructions, it would interfere with the belt's movement, acting as a brake, essentially. To remedy this, I cut a piece of 0.03" plastic shim for the rubber to sit atop, so the belt could slide underneath it:
Stretching the belt over the rollers is a bit tricky. The instructions suggest snapping the front roller into place first, then the back one. For me it worked better to position the front roller just prior to snapping it in, snapping in the back roller, then finishing the front one. In the course of doing this the belt caught on one of the center shaft supports, which put a raised burble in it. Without a completely flat build surface, extrusion errors are all but certain. I was worried that I would have to do some major disassembly to replace the belt with one of the provided spares. In an effort to avoid that, I applied my heat gun to it, and the burble flattened out. Phew!
Here are photos of the top and bottom of the "completed" automated build platform. (I put "completed" in quotes, because I see I left out some screws.)
This part of the build took most of the day. I don't see how Rich ever got this done in eight hours. Maybe it was forced child labor instead of swearing that sped things up for him.
So far, I'm pretty happy with the materials and instructions. The plywood should have been a much higher quality than what was provided. But I was happy to see extra material provided where one might lose it or screw up cutting it. I'm still paranoid about dropping a small part on the floor, as I did today with one of the nylon washers. I was lucky to find it.
And when I get frustrated, I can just look out my shop window and enjoy the local "fawna":
-Phil
IIRC someone has used some clear tape to temporarely fix those nuts at the slots.
-Phil
Rich H
Tonight I finished the Y-axis platform, which holds the X-axis slides and stepper motor. Things seemed to go swimmingly, and I almost finished it until I realized some things were fishy about how the X-axis belt was supposed to get tightened. For one thing, the tightening mechanism consists of slots in the bare wood, against which small-diameter Allen screws get tightened. This is a recipe for trouble because, once the heads bite into the wood, further small adjustments would be nearly impossible, since the heads would seek their prior indentations.
The other problem is that two of the screws lie completely underneath one of the X-axis slides. Tightening them -- even with the ball-end Allen wrench provided -- is simply not possible.
So I took everything apart and laser-cut some Delrin gaskets to keep the screws from biting into the wood:
Next, I tightened the ones that would lie under the slide until the motor could not be moved, then backed them off a little. After reassembling everything, I tensioned the belt by pulling the motor against the endplate and tightened the two screws that I could still reach to hold it in place. This caused the motor to tilt a little, due to the soft cork gasket between it and the wood. But I'm not worried about the belt binding as a consequence.
In the course of pulling the motor against the endplate, I managed to crack the wood at a point that's very thin and weak:
A couple drops of Super Glue were all it took to fix the problem.
Here's the completed Y-stage:
-Phil
I don't think much dis-assembly would be required to use the heated build platform alone. The kit comes with separate parts for each. I think you would only need to remove the bearings and the pcb. But, since you already have it completed - might as well play with it for a while.
It looks like you have end stops on both sides of the Y stage - how many did your kit come with? I only have three. One on the right side of the Y stage (min X), one on the acrylic floor (min Y) and one to the right of the Z stepper for max Z.
Rich H
Okay, it has been a slow day so far. Every Saturday, my not-so-brief interlude with Will Shortz's torment takes precedence over everything else. But that's over, and I completed the Z stage platform. I've got some reservations about this unit. The Z nut (circled below) that supports the entire platform is in the top section. This means that the entire weight of the platform has to be supported by T-slot joints that are in tension rather than compression. These are not the kind of joints you want in tension, since the screw heads are so small and the nuts are pressed against the plywood's very soft core.
But I'm going to give this one the benefit of the doubt and press ahead. I suspect I'll be readdressing this somehow -- if not immediately, then later when the Z stage begins to sag.
-Phil
I agree completely about the design of the Z stage - lots of room for improvements.
Rich H
I have the Moons motor. This is the photo in the instructions I was going by:
It looks like the nut protrudes into the hole from the bottom. But the nut I was provided does not fit into the hole.
-Phil
Here's a photo:
The spacers get glued to the feet at the bottom of the arch; and the feet, in turn, get bolted to the Z platform.
I'm still Loctiting the screws, but it's tedious, and Loctite is really messy stuff to work with -- nearly as runny as diesel fuel or soy sauce. Most of the smudges you see on the wood parts are from dirty Loctite fingers, not laser-cutting ash. I've had to disassemble some of the Loctited joints, and I know from that experience that the stuff works. (I hope it doesn't attack acrylic!)
-Phil
I used Goop to glue the acrylic feet on. It holds very, very well. I know this because my son glued one on backwards and I had to pry it off.
Rich H
-Phil