Giving Up on Linear Bearings

I’ve officially given up on linear bearings. Two weeks ago I installed the linear bearings in my MakerBot, but didn’t like the initial noise results. Today I finished removing them and putting the old copper bushings back.

The linear bearings were amazingly smooth. If you put on one a rod and started tilting it, it would roll off the rod very quickly. There was almost no friction. In contrast, the copper bushings hold on for at least 5 to 10 degrees more before they start to move, and they have enough drag that they don’t pick up nearly as much speed.

But the noise drove me nuts. When I asked about noise solutions on the MakerBot google group they gave me some ideas, but I just couldn’t solve it. I got some white lithium grease, but putting that in the bearings made almost no difference (works nice on the bushings though). Everyone recommended PTFE based grease but I couldn’t find it locally and didn’t care enough to order it and wait.

If I owned a house where I could put the Thing-o-Matic a few rooms away, I would probably leave the linear bearings in. But in my one room apartment, I have to live right next to the noise and it was far too loud.

As long as my bot is open, I’ve been doing a few other upgrades. I installed M_G’s tensioning pieces, which worked great. When I reassembled my X axis is was pretty cool to be able to turn one bolt and have the slack in the belt pulled up. It’s so much easier than loosening four bolts, pulling the motor, and trying to hold that while tightening things back up.

I added Campbell’s Y-axis idler and I plan to install Joakim’s X follower. I made both when I first got my printer, but things weren’t calibrated well enough at that point so neither fit (nor worked) very well. Now that I know what I’m doing I know I can do much better. The Y idler should help with the tension (and hopefully reduce noise), while the X follower should make the X axis much smoother since it cuts the number of bushings in half. I also saw a reference to epideth’s Z axis bearings which I’d also like to. I don’t like how close the bushings on the Z axis are, the make it possible for the whole thing to wobble because it can’t support it’s own weight very well. Once the weight of the giant MK6 motor was gone, I was amazed how far the end of the Z platform could bounce if I pushed it with my finger. Having those long supports should help.

Last I finally got around to installing static drain lines which I’ve been meaning to do for over a year. When the air gets dry this time of year I start to get zapped by everything in my apartment, so I get really worried that I’m going to damage my MakerBot. I also used up a ton of 1/4″ kapton tape (mine came from MakerBot) to tie up some of the loose wires in the base, which really cleaned things up. I don’t know why I didn’t think of it before.  I cut pieces just a few inches long and wrapped them around the groups of wires every few inches.

After that I’d just like to get back to printing little things and painting them. That was quite a but of fun but I haven’t been able to try it in a long time. After all my tinkering it’s clear I’m pushing the Thing-o-Matic a bit, I’m wondering when I should give up and decide to buy a new printer. I’m not sure which model I’d want though. Make’s 3D printer guide was a fun read, but didn’t give me a clear winner.

Ultimakers have always looked nice, and I like that they’ve moved to cartridge heaters, but the lack of a heated bed means printing ABS parts would have to be small. I also really like Sailfish and have no experience with the Marlin firmware.

The Replicator 2 looks nice, and I’ve had great experiences with Makerbot. But I’m not sure about Makerware and would be happy to get away from Skeinforge. I hear so many great things about Slic3r, I think I’d be happy to move to it. While the Replicator 2 is much closer to an appliance (which is a good thing at this point), it doesn’t do ABS (the Replicator 2X will). The biggest con is that those printers are very expensive.

All of this is rather academic, as I’m not that interested in spending the money right now. But I keep thinking about it.

Let The Upgrades Commence (and a Brain Slug)

Upgrade Parts

Around November 6th I received my new extruder. I really wish I had ordered earlier as I ended up having to wait quite a while since I was so far back in line. It’s amazing how much smaller the thing is than my old MK6.

I’ve had some adventures with it. I didn’t like the gear it came with, it required way too much tension for my taste. I switched it to a Makerbot MK7 gear and the extruder is doing a great job. The extruder block and metal adjustment screw that QU-BD uses for tension work very well. All the parts shown in this post were printed with it. By the way, when installing something new, don’t forget the mods you’ve already done. I accidentally screwed through the lighting I had installed while putting the new extruder in. Oops.

I wanted to use a bearing based extruder drive again, so as one of my final prints I made Jag’s extruder drive (see No Bots Left Working). It was very easy to install, but I ended up with the oddest problem. In the middle of a larger print (the X carriage shown above) the printer jammed. When I opened up the extruder I found that it was clogged with plastic shavings. It seems that the bearing was positioned slightly below the drive gear, causing the filament to push against the side of the feed tube.

So I switched back to QU-BD’s parts and was able to print no problem. I’ve made whosawhatsis’s Minimalistic MK7 Replacement and ran some plastic through it, but I haven’t used it for a real print yet. I’m a little worried about the amount of tension that the spring holds, but it did work great for the quick test I gave it.

But the bigger deal is now that my printer is running again, I can finally do a bunch of upgrades I’ve had planned. I bought a bunch of LMB6UU linear bearings which form the core of the upgrades I performed. My hope was that this would allow me to speed my bot up and quiet it down a bit.

First I replaced the bearings on the Z axis using dnewman’s spacers. I have pictures of that process and the rest of my mods in my Flickr stream, which I should make a post on later. Next I put a pair of linear bearings on the Y axis with Jag’s Y Axis Bearing Holder/Spacer. To finish the bearing replacements I printed out MakeALot’s Linear Bearing X Axis Carriage for ToM and installed it. Like some of the others in the comments on the Thingiverse page, the parts that are designed to hold the bearings in place snapped on me, but I was planning on using the zip ties anyway.

With those mods installed, it is much easier to push the axis around, but things are not quieter. For some reason the Y axis seems to make even more noise than it used to, but the vibration goes away if I put just a bit of weight on the right side (such as resting a finger on it). I haven’t had a chance to look into that yet, but I’m hoping I can fix it. My apartment isn’t very big so I can’t put the printer a couple of rooms away where the noise won’t bother me; I also worry about the noise annoying my neighbors.

As long as I had everything apart, I decided to install famulus’s HBP Quick Leveler Redux. My old solution basically worked the same way, except there were no finger nuts so things had to be adjusted with needle nose pliers, which was very difficult. The new levelers were very easy to adjust, but I’m not sure they’ll stay installed. On the Thingiverse page people only seem to add levelers to the four corners, but I’m crazy and added them to all 8 outer points. That alone is odd because I added 2 additional bolts to make it easier to level the bed completely. Well I had to remove the two thumbwheels off the right side of the bed since they interfered with the X limit switch. The thumbwheels on the front corners mean that the bot can’t access the entire build surface; when trying to use the back corners the thumbwheels on the front can hit the sides of the front panel. Leveling my bed before was a big process, but it only had to be done once or twice (tip: thread-lock means the adjustments won’t shake loose).

It’s nice to be up and running again. The MK7/8 style extruder is very nice, and heats up even faster than my old MK6+. In fact, it makes it much more obvious just how slow the HBP is to heat up. I want to try whosawhatsis’s tensioner for a while, and I need to get things perfectly calibrated (I did a quick adjust on the great profile created by Makerblock’s Profile Maker). Then comes the real fun of upgrading to Sailfish and SF50 and seeing just how fast my printer can go. Plus, I have a roll of PLA I’m itching to try out. I really want to get back to printing out little objects so I can paint them and just add new toys to my desk.

To close this post, I’ll put up a picture of my latest Crochet creation. One day in late October I decided to make a second mini-Brain Slug, and it only took me about an hour and a half. Now we’s sitting on my desk, keeping Blinky in line.

Mini Brain Slug

No Bots Left Working

MK7 Fan Shroud

What you see above is the final print from my Thing-o-Matic for a while. I finally finished off the last of the filament I own. In fact, just like when I ran out of my original natural color filament I had to switch colors mid-print (using Jetty’s excellent firmware‘s pause feature) just to avoid running out of plastic.

That’s a MK7 fan holder/print cooler. Right before that I printed a MK7 ball bearing extruder drive. I had wanted to upgrade to a MK7 extruder and start using 1.75mm filament, but there was no point in reconfiguring my machine while I still had 3mm plastic. I’ve ordered new plastic (white PLA and blue ABS), and it should arrive tomorrow. Unfortunately it looks like it will be at least two weeks before I’ll get my new extruder, so my Makerbot is getting a rest.

For extra fun, I broke my Polargraph last week. After printing out the new case, I hooked things back up in a hurry. Well I should have thought harder about that because I got wires crossed on the pen lift servo and fried it. Dang. I got a new servo in today, so I should be back in business. I’ll have to play with it tomorrow. I think I need to adjust the position the servo uses to lift the pen up, I’m not sure it’s far enough at the default with the new servo.

Building and Running My Polargraph SD

Complex print (better picture)

Once I received the kit, it didn’t take me too long to build. I used RJ-11 jacks and cables to connect the motors and gondola to the controller board. I started to print out the Polargraph SD’s case after it was posted to Thingiverse this morning. It’s going to take some time, the bottom of the case is just a little too big for my Thing-o-Matic, so I had to slice it into two pieces.

It certainly takes a long time to print, so I’m glad I waited to get a version that could run without a computer attached (although I suppose that could have been my Raspberry Pi’s job). Since nothing is being heated over 220° C, I don’t worry about leaving it alone. I’ve been starting prints before I leave for work in the morning, so they’re ready when I get home. That didn’t work out perfectly today, when this happened:

Solid square GameBoy

It had been going for about 7 hours. I’ve been trying the different printing styles, and this was called “solid square wave”. That seems to mean that every pixel that isn’t blank is solid black. Since it wasn’t turning out to be much of a drawing, I stopped the print.

Polargraph brownout

I’ve had other adventures too. We had a summer storm last week that caused two very short brownouts. They were long enough to trigger the alarm on my UPS, but not long enough to cause problems with my TV, XBox 360 or other electronics. The capacitor’s in the Arduino’s power supply kept it running, it never missed a step.

On the other hand, the steppers didn’t fare as well. It looks like when the brownouts occurred, there wasn’t enough current to keep the stepper motor’s locked in position, the pen fell down the paper. That caused the neat little mistake above. I’m using a giant linear wall-wart for a power supply, and I guess it doesn’t have enough output filtering to be able to supply the motors during those fractions of a second.

I’ve had a few other adventures. At one point I accidentally changed the pen width to be much too wide. This caused drawings to look too sparse (first attempt), instead of having the contrast it should.

I also had a positioning problem caused by running firmware that was too bleeding-edge out of the SVN tree. It meant I got to help debug the problem, which Sandy quickly fixed. When I tried the Norwegian drawing style, I ran into an issue with the way The Gimp made the headers on PGM files, which I fixed myself. That meant I wrote and submitted my first patch to an open source project.

How Does Accelerated Printing Look?

Accelerated printing

Since I recently got accelerated printing working using Jetty’s firmware, I thought I would try to see what kind of quality difference I would get. The cute little octopus was designed by Makerbot, and I knew I had to print him. The copy on the left was printed without acceleration, using the standard 30 mm/s feedrate. He took about 45 minutes to print (he’s about 1.5″ tall).

The octopus on the right was printed accelerated at 75 mm/s, and took about 20 minutes. He actually came out pretty well. Some of the layers are slightly misaligned, but I know that my settings need more tweaking. The hovercar in front was actually my first really successful accelerated print. He was printed a few weeks ago, also at 75 mm/s.

The two Mac Plus models are a different story. They were the first objects I tried to at high speed after getting the calibration cubes to work well.  I believe the one on the right was printed first, but it was printed at 100 mm/s. The one of the left was printed at 75 mm/s and did better, but I think the model was just too small to be printed at such high speed. Since I was only using 15% infill, the layers took so little time I don’t think they were cooling enough before the next layer started, causing the poor finish.

I’ve been playing with accelerated printing on and off, I still need to do some tweaking. Stuff I want to come out well (such as my Raspberry Pi case, and a case I’m printing for my Polargraph SD) I still print unaccelerated.

What To Do With A Raspberry Pi?

Raspberry Pi case

Earlier this year when my number came up in the queue, I put in my order for a Raspberry Pi. It arrived in the last week or so, and I printed out HansH’s case to give it some protection and style. The print took surprisingly little time even though it wasn’t accelerated.

The only problem is I haven’t figured out what to do with it yet. I use Rogue Ameoba’s Radioshift (which apparently is no longer developed) to record two radio shows, but they don’t show up as podcasts in iTunes. I’ve been thinking of using the Pi to server up those files to iTunes so they would show up correctly.

Painting Makerbotted Figures


The first model I painted was my B-17 Flying Fortress. In that post I said I tried a cheap airbrush with a propellant can and it didn’t work. That model was largely hand painted.

But I haven’t stopped experimenting. For Christmas I got an Airbrush Depot TC-20T compress and SB84 airbrush. The compress is very nice. It’s not all that loud and having the tank means that it doesn’t have to run constantly. I’m always worried about annoying my downstairs neighbors, so that’s a serious plus.

As for the airbrush, I though it was pretty good. While it was a huge step up from the external mix piece of plastic junk I tried before, it was tough to clean. It also needed quite a bit of air to spray paint. I generally used the brush with the nozzle open all the way to get enough paint. This may be because it’s a side-loading airbrush. A month or two ago I was reassembling it after cleaning, and broke the nozzle when I overtightened it. I was going to buy a new one when I found that an Iwata wouldn’t cost too much more (I thought they were all $250+).

So I bought an Iwata-Medea Eclipse HP CS. As soon as I tried the Eclipse I knew what a huge difference there was. I knew people online liked them, but wow. It’s top-loading, and that makes it MUCH easier to clean. Pulling the lever back all the way to release the maximum amount of paint just drenches things, which is fantastic. The SB might as well have been an on-off device. A side effect of all this is that it doesn’t need as much air. When you have it in your hand, it’s easy to tell how much higher the manufacturing standards are. Add a quick disconnect and life is much easier.

So with my new tools I’ve been having a ton of fun painting models that I printed out with my Makerbot. Besides the Pikachu above, I’ve painted Alot, Piccolo, a Stegosaurus, a Cyberman, Bender, Purple Tentacle, and various pet monsters by Andreas.

I’ve figured out quite a bit while doing it. Preparing the model well before putting the primer on makes a big difference. It’s so easy for the paint to flake off afterwards, something you can see on Bender. Another problem I’ve had is paint colors. I’ve been using Createx opaque paint and mixing the colors myself. This has been fun but I quickly learned a lesson: mix more than you need and save it. With Bender and each of the pet monsters, I ended up having to repaint large portions of the model because I needed to put the base color back on and couldn’t match it closely enough.

I’ve found that Testor’s gray primer works great, and you can buy straight liquid so you can airbrush it on. For sealing the finished models I tried a few things before I found Testor’s Dullcote. It smells horrible, and I worry that I’m going to damage my airbrush with it. Next time, I think I’ll just buy the little spray cans instead. But unlike some of the other clear coats I found, it doesn’t change the colors making everything look less saturated and more boring.

I didn’t really have a use for my Makerbot when I bought it, but I think I may have found it. Since I’m close to getting to getting Jetty’s accelerated firmware fully calibrated, I’m looking forward to printing larger objects without it taking as long. My mistake the first few times? When you up the speed, you must up the flow rate. I kept forgetting to do that, which is why the extruder wasn’t putting out nearly enough plastic.

Honda Odyssey Bumper Fix

Van fix (distance)

A few months ago I ended up damaging the bumper on my Honda Odyssey minivan. One day I noticed it looked like my bumper was falling off. As it turned out, the end of the bumper broke off right at the point where it was attached to the frame. It probably got caught on something when I was backing up; or maybe someone just hit my car.

Either way, it was a bit worrying. I didn’t want my bumper to fall off in traffic, and I didn’t want to risk going into an automatic car wash. Duct tape (you can remnants in the photo above) didn’t hold well and looked even worse.

So I did what anyone with a Makerbot would do, I designed and printed a fix. It glues onto the end of the bumper and provides a hole for the bolt that keeps the bumper on the car. I’ve been driving around with it for a few weeks now and it works great.

My Odyssey Bumper Fix is available on Thingiverse, if you should have the same problem.