Friday, May 18, 2012

Mark II

I printed a Mark II robot friend today from Thingiverse.  I made mine for my nephew, and I'm sure the rest of my nephews will want one as soon as they see it.  Pablo did a great job on this one.  Printed full size, Mark II stands about 9 inches high.   I would recommend printing the "pins" and "joints" slightly smaller so they fit without trimming.

Plastruder Clone Update

I've been using my Plastruder Clone for a number of prints and I am very happy with it.  I print between 70 and 80mm/s with out any problem.  The increased weight on the X carriage from the larger geared stepper means I can't print much higher without crazy vibration.

I did notice an issue that I never experienced with the hobbled bold on my Wade's - clogging.  I have had an issue multiple times where the drive pulley's teeth will clog.  This has always been my fault.  It always happens if I set my Z height too low.  As long as I avoid this, I am completely fine.

I never had this problem before with my wades, it would just squash out the abs and make the first layer look like hell, but never clogged.

Now if my drive pulley clogs, I'll get a very weak infill on my first layer and subsequent layers will lack in density once the pulley spins around to the clogged position.  

Moral of the story: be precise with your Z heights.    Other than that, everything is going well, even with the incorrect stepper.

Tuesday, May 15, 2012

New Printer Build!

I'm in the process of obtaining all of the required parts to build my Pocket Printer derivative.  As stated previously, I am building mine with the standard 9x9"(ish) build area associated with a Prusa.  This way I can use the Prusa Mk1 PCB heated bed. 

I purchased the 8020 extrusions from Misumi. You can get it cut to specific lengths and have them tap the ends for you too.  I will post more information as it progresses.

Monday, May 14, 2012


Be sure to check out the webstore for RepRap Printer Parts.  Different colors available.  If you have any questions/requests, let me know.

Thursday, May 10, 2012

Plastruder Clone

I have read many posts and reviews complimenting Makergear's Plastruder.  They charge $170 for the whole kit.  I already had my J-Head hotend and could print the parts myself so I decided to try and build a clone.  I put this Plastruder clone on my Prusa Mendel i2.  Here is the build process.  Hopefully this saves someone some time/money.   

Drive Gear: ($12 + $20 for machining = $32)

I purchased a replacement mk6/mk7 drive pulley from a seller on eBay. (Makerbot sells them here too, but they weren't in stock when I started this project.)  The gear had a 5mm for a standard Nema17 motor shaft.  It needed to be 8mm to fit the geared stepper I used for this (see below), so I took it to a small machine shop around the corner and they opened it up for me.  It cost me $20 but its perfect and I know I would have screwed it up if I did it on my own.  It's 305 Stainless, so it wouldn't be the easiest thing to do on your own.

Geared Stepper: ($34 + shipping = ~$60)

I kind of screwed up here.  I really should have done a little more research before I bought this stepper.  I noticed after I already had this stepper in my possession that Makergear provides the manufacturer and model number on their website for the exact motor they use.

Side note:  Makergear has two different motors listed for their plastruders.  One is a 14:1 gear ratio and the other is a 5:1 ratio.  I assume the difference here is it's intended use.  The 14:1 has more torque, therefore I have to imagine when a plastruder is used with 3mm filament and a 0.35mm nozzle, this is the motor of choice. (Although I don't know that for sure, but check below for my reasoning.) 

You can find the "correct" motors here. These motors are a bit more expensive and I have no idea how much shipping would cost.

I didn't notice this and decided to pick out my own geared stepper blindly.  I chose this geared stepper by Phidgets. ( sells these as well, and they may have cheaper shipping).  It has a 5:1 gear ratio and a respectable 20 kg-cm torque rating  (16kg-cm holding torque).  In hindsight, it's torque is slightly less than the 26kg-cm that the "correct" Kysan stepper has.  (See below).

Printed Parts: (Self Printed = $0)

I found this on thingiverse, and used it for my filament drive body.  I liked the rear facing motor because it didn't decrease my X distance at all.  (The size of the x carriage, driver body/motor is still shorter than my Wades on my normal x carriage so my Z clearance actually increased by a few mm.) 

I used this for my new X carriage.  I already had linear bearings so this worked perfectly. 

Both of these objects absolutely need to be printed with support.  So be patient and clean them properly after printing. 

I had to make my own J-Head mounting plate.  You can see in the pictures its the white block with the split in the middle directly under the blue filament drive body.  Its basically a collar that fits around the groove on the J-Head body.  While it works flawlessly, its not the best solution since it requires me to remove the entire extruder from the X carriage to change hotends. (I can upload the design to thingiverse if anyone is actually interested in using it, just let me know.)

Hardware: (Stuff laying around = $0)

5x 5mm bolts - 2 to connect motor to drive body, 2 to hold everything to the X carriage, 1 to hold the idler bearing block

2x long bolts w/nuts - used to hold idler bearing block closed.  Probably should use springs, I didn't but I make sure they are tight often.

1x 608 bearing - idler

8mm smooth rod - idler

Total: ~$92

End Result:

This is made for 3mm abs filament with a 0.5mm nozzle.  It works perfectly as long as the bolts holding the idler body closed are tight. 

Side Note:  I originally tried this with my new 0.35 J-Head hot end.  I couldn't get it to work correctly.  I don't think the motor has enough torque to push the large 3mm filament into the smaller 0.35mm nozzle.  If I tightened down the bolts to a point where it would push the filament, the motor was skipping steps.  Increasing the current to the motor eventually resulting in even more missed steps.  I imagine this may work better for 1.75mm with the 0.35mm nozzle but I haven't tried it.  The Kysan 14:1 ratio model has a holding torque of 26kg-cm. (compared to the Phidgets' ~16kg-cm)  I may purchase one of these in the future and see if they helps my problem. 


My Plastruder Clone works and works well (as long as I stick with the 0.5mm nozzle.)  I do notice a slight increase in print quality over my previous Wades ( but I may just be bias).  It was definitely cheaper than buying a full kit from Makergear, since I didn't need the majority of the parts included in the kit.  I'm not sure if you priced it all out separately if you would end up saving any money, maybe?  But its always fun to do things yourself!  Let me know if anyone has any questions/concerns.