February 11, 2010 – MakerBlock

Where do you get bearings?

A little while ago I shared my thought about picking up cheap bearings by going to a used/recycled sporting goods store. However, they’re really light on selection.

Where would you go to pick up 626 bearings or 606 bearings? (I seriously have no clue).

Differences between MakerBot Batch 9 and 10

Someone recently posted on the MakerBot operators group that there were some minor steps missing on the MakerBot Batch 10 instructions. Just so you know the three things that person pointed out were fixed almost immediately. You’re NEVER going to get that kind of service from IKEA.

In any case, this gave me the idea of perusing the Batch 10 instructions to see how they differ from my Batch 9 ‘bot. Here’s what I’ve noticed:

Different build order. The Batch 9 ‘bot instructions show the body being built first, then the XY stage, then the plastruder. Batch 10 shows the XY stage, then body, then plastruder. I think you could probably build the Batch 9 ‘bot in the Batch 10 order without a problem.
Different Y stage caps. Batch 10 ‘bots appear to be using an Y stage cap that has more room for the pulley that rides on the Y stage. My guess is that this will probably buy you a few precious millimeters of print space. (The pictures say X stage end caps… but it looks like the Y stage to me.)
Different Y stage pulley. Unlike my batch 9 bot, these instructions show assembly with a manufactured toothed idler pulley. I have no idea what benefit is conferred by having teeth on that pulley. Perhaps it is less prone to slipping on the belt? Perhaps it makes it easier to tension the Y pulley without disassembling the Y stage?
Different X axis pulley. This manufactured toothed idler pulley looks similar to the one on the Y stage.

Why the toothed idler pulleys?

MakerBot Cupcake CNC print resolution

Some people have asked me about the MakerBot’s print resolution. Although this information can be found on the MakerBot wiki, there’s no harm in disseminating this data. ¹ Before I get into some of the technical stuff, let me just say this – the print resolution is pretty freaking good for a $750 DIY robot and it will give a $15,000 commercial printer a run for it’s money.

As a printer that can create objects in three dimensions the normal two-dimensional printer resolution jargon of “DPI” or “dots per inch” doesn’t mean much. The printing resolution for the X/Y axes is 0.085mm and the resolution for the Z axis is 3.125 microns. Most of the time you’re going to have a Z axis resolution of about 1/3 of a millimeter. If you print with layers much smaller than that it will take forever to print without a huge increase in quality.

Or, to put it another way… if you were to hand me two objects one printed on a MakerBot and one printed on a commercial printer, I’m going to ask you why the heck one of them costs $14,000 more than the other. I’ve printed some pretty intricate and detailed stuff on my MakerBot. As I tune it I hope to improve it even more.

If you haven’t poked around the website, I highly recommend it. There’s a lot of information about the Cupcake CNC, RepRap, fused deposition modeling, robots, and all sorts of stuff. [↩]

Blind reading the blind…

I just noticed there’s a Twitter feed ( http://twitter.com/CanMakeIt ) following this blog. Since my post titles tend to be more whimsical and self-referential than informative, I feel kinda bad for anyone mislead into clicking on the titles.

If you’re one of those who came to this blog wondering what the hell I’m babbling about… um, sorry. I’m frequently off topic. Sorry for clogging up your RepRap aggregated feed!

Tea cups

I designed and printed some tiny tea cups to go with my tiny teapot. Unfortunately the two models I tried to print (one in PLA and the other in ABS) turned out very very badly due to the clogged extruder barrel. However, I rather like the design and look forward to printing it properly.

Repairing ABS parts

The spout on the black teapot on the left snapped off as I was trying to clean the model. I don’t have any ABS glue lying around so I tried white glue – which didn’t work at all. Later I held up the broken piece and the body of the teapot to my hot extruder barrel and melted them back together. Clearly not a recommended way to repair a part – but it’s been pretty effective.