Cyrozap's Tech Projects

Computers. Circuits. Code.

Any Recommendations for Prusa Mendel Parts?

Progress on the RepRap has slowed to a crawl and it's really bumming me out. Building from kits is SO much easier than sourcing the parts yourself. I've probably gotten the final cost estimate into the $600-$700 range by now.

Anyway, I need your help. I just need to print out the new X-carriage, get some M3x25mm bolts, buy some MDF for the Y-stage, and get a hot end. However, I don't really know what to get. What are the recommended dimensions for the Y-stage (LM8UU bearings)? What's the best hot-end for 3mm PLA that I can get in the U.S. for a Wades extruder?

Feel free to comment with your suggestions!

Early Christmas Gifts Are Awesome

The MK5 parts kit!

My dad got me a MK5 kit for Christmas after my MK4 broke for the 3rd time in a few months (PTFE insulators are annoying—I think my thermistor table was wrong). I have since put it together and am currently printing out the Holiday Prusa Mendel on Thingiverse with it. Talk about the gift that keeps on giving! :)

However, there were some problems I noticed:
- Thermistor read wrong temps—ABS now likes to melt at 200C
- Solder joints on power resistors melt partially when running at 200C
- The online instructions for putting it together didn't account for certain changes in the kit; for instance, it comes with two crimp connectors that are never explained.

I did make some improvements, however:
- Added thermal paste between power resistors and aluminum block
- Epoxy used to glue together base-plates to the legs of the extruder holder

My current grievances:
- I don't like that the solder joints are melting and cooling—I don't want to have the risk of breathing in those bad fumes.
- Teflon on nozzle is coming off tip

Final thoughts:
- If it doesn't work flawlessly, at least it works a lot more reliably than the MK4!

Interesting things I noticed today while writing this:
- The server is running quite quickly...
- The 5.1MP Sony Cyber-shot DSC-P93 I used to take the picture in this post (I got it for free from a friend of my dad) has hardly any image sensor noise. This is amazing compared to the amount of sensor noise in my 5.0MP Canon PowerShot S2 IS (consumer-grade DSLR).

MakerBot Fixes and Upgrades

Well, I just bought some new parts for my Makerbot. First, because my build platform broke, I bought the MakerBot Heated Build Platform Kit. I decided that, since I was switching back to ABS, I should be using a heated platform. I also didn't want to pay for a normal build platform now and pay for a heated build platform later when I'll really want it. Second, I bought the Magnetic Rotary Encoder PCB. I got 3 samples of the chip a while ago, so I just bought this because it may come in handy in the future. Also, I wanted to practice soldering SMT parts by hand. Finally, I bought the MK5 Drive Gear Upgrade Kit because it's just so much better than the current one.

PLA!

A few days ago, I ordered some PLA (from UltiMachine, at $47.50) so I could print out larger objects without warping. It's arrived, and now I have to figure out how to modify my MakerBot to use it. I found this thread helpful.

PLA

Just so you know, MakerBot Industries is also selling PLA, but it is 4032D, and is currently on sale at $60 (and will rise to $80 on Monday). Supposedly, 4032D is better because it has a more ABS-like melting point so it can be used in a MakerBot more easily, but I've heard 4042D works fine.

Failures and Succeses

This post summarizes the events of the past few days:

  • MakerBot randomly stops during large print (Mendel extruder), causing blob; blob makes print fail epicly.
  • Happens again; no idea what's going wrong.
  • I tighten the X/Y belts.
  • Happens AGAIN!
  • I sleep on the thought.
  • I tighten down the extruder.
  • I take a trip online to the MakerBot Google group; find out what I have to do.
  • I fix it.
  • I happily print out Mendel parts.
  • :D

Mendel Extruder

In Other News: Fixing the "Fixed" Extruder

I believe that the repairs I just performed on the extruder are going to work this time! I tried building a test dodecahedron recently and my extruder just stalled on me. This has happened before, but I think I have found the problem. The pinch wheel was allowing the filament to slip next to it during extrusion, causing it to lose contact with the idler wheel and stop extruding to fix this, I simply filed down the pinch wheel. If this works, great! If not, I'll file down the pinch wheel more until it is impossible for the filament to slip. Actually, I think I'll just file it down anyways to prevent making ANOTHER cracked idler wheel.

Rebuilt Extruder Creates More Problems

As I said in the last update for this, I rebuilt the extruder. Yay!

The rebuilt extruder

But there is a slight problem: the extruder, for some reason, extruded for a while, but then just stopped. I think I just need to tighten it down better (I did it by hand first). Ugh. This run-it-for-a-bit-and-then-it-breaks-and-I-have-to-fix-it routine is really getting on my nerves.

Extruder rebuilt!

Self-explanatory title is self-explanatory.

Long story short, I rebuilt the extruder for my MakerBot and will be testing it tomorrow. Then I will be able to see how well having less ceramic tape on the heater barrel works.

Priorities

Ok, here goes:
I recieved the parts for the extruder on Monday, but didn't even touch them until Wednesday and I haven't yet attached the nichrome wire, thermistor, and ceramic tape to the heater barrel nor replaced the Idler Wheel yet due to time constraints. It's not that I don't have enough time—in fact I have plenty of time—but I don't have enough contiguous time. I need a good, constant 3-5 hours of total zen/focus while working toward the goal, otherwise, things could go horribly wrong. I need total concentration when I work.

Why do I need 3-5 hours to work?
Well, I first need to fix the hardware issues, then I need to figure out optimal skeinforge settings so this same problem doesn't happen again. Namely what I need to do is adjust the temperature settings to accomodate the lesser amount of ceramic tape I will be putting on the extruder. I'll probably keep the speed and infill density stuff the same as before I got the new skeinforge. I may want to print out a few dodecahedrons with the default settings first, then with my own, then I will compare the two and pick the better settings set.

I hope to be working on it over Thanksgiving weekend.

MakerBot Extruder Woes

So I decide to finally fix the extruder. In doing so, I found more problems than I thought existed.

Problems:

  1. Idler Wheel has cracked
  2. Insulator Retainer has cracked
  3. Nichrome wire insulation has turned to powder
  4. Overheating caused kapton tape and ceramic tape to burn
  5. The barrel and nozzle are full of eels ABS.

I have ordered replacement parts.