Monday, August 16, 2010

New ABS Plastic in stock!


We have new ABS plastic in stock in the colors Natural/White and Black in stock. The plastic is made in Germany and comes on spools that are easier to unroll than the coils of Natural/White ABS we have.

Saturday, July 10, 2010

Testing Wade's extruder drive [Update]

I'm currently testing Wade's extruder with Nophead's Gear and Idler bracket on my Shapercube. Thanks to Prusajr's design, I was able to easily mount it. The mount with cable binders is not bullet proof but it gets the job done.


The dark stuff is "WEICON Flex+bond" glue, which I had only in grey colour. A combination of production error and too much force caused delamination. The glue holds it together nicely.

The main thing I dislike on Wade's extruder until now is the serviceability. When something is blocking the extruder, the drive teeth eat the filament quite fast. For example, a failed part after this happens looks like this:

And the drive looks like this:
Wade's design could be improved if this drive would be accessible from the top or side, without having to disassemble half of the parts to get there. I'll try implementing this in the next days.

I haven't found the perfect way to clean this up, yet. I was thinking about a screw on the other side that rotates with the same speed of the gear, but that would add a lot of complexity to it, because a second gearing would be required.
Another idea I had is adding a small wire brush, but that would not be effective on the plastic that got inside the teeth.

[Update]
I'm having success with drive gears made out of a M6 tap. The wider teeth won't eat the filament on normal operation. Even if, a short spray out of ice spray does the job.



Tuesday, June 15, 2010

PCB Heatbed Prototype

Thanks to Prusajr I've got a prototype PCB Heatbed running on my ShaperCube.

This heatbed is an etched, single sided 220x250mm big PCB, ~1,5mm thick in total with 35ym coppper thickness.

Mounting it

The PCB itself is not flat, but can be bent slightly. Similar to Prusajr's design, I utilized magnets to keep the sides down.

The Magnets I use are 9mm in diameter and 5mm thick NdFeB ones. They have a catch: The ones I use can only withstand temperatures up to 80°C. Because of that, I didn't glue them onto the PCB, but I glued some strips of steel tape onto it with temperature resistant glue.

I made a pile of 2 magnets each on four sides of an MDF board hoping to keep the temperature down a bit. The magnets are glued to the MDF using some expoy glue. So far, this works nicely.

After a couple hours of operation, the glue on the middle piece failed. The ones on the side don't get that hot and are still working.

As it turns out, magnets are not the most elegant way to mount it but probably the easiest non-permanent "do-it-yourself" way.

Electrical issues

The heatbed needs a lot of power. It draws 11A @ 12V when cold. Using this kind of power from a ATX PSU requires to use two plugs and probably a very good PSU. I had problems that the voltage on the +12V rail dropped too much on my 400W PSU (which is appearantly rated for 16A on the +12V rail). Currently I'm using an external power supply for the heatbed.

Heating up & Polyimide Tape

To stick ABS onto the heatbed, I use Polyimide tape. Those can be ordered in the same size as the PCB is. Large strips of Polyimide tape are a bit tricky to get on to the PCB without air bubbles. The factory actually suggested a machine to roll it onto, but from $350 a bit pricey.

Anyone else use large tape and have different experience?

Printing quality

Apart from some air bubbles I had, the parts come out perfectly flat. A bit of warping still appears on the sides of the heatbed. Nophead wrote about this and has a nice solution for his Mendel.

The bigger problem I still see is in adjusting the heatbed. If the nozzle height is not set correctly, it can easily snap traces on the PCB. Once snapped, they can be repaired with solder and some sanding, but the results are far from perfect.

I was thinking of putting a thin sheet of aluminium on top of the heatbed to protect it. But this would need a better way of mounting it.

Thursday, April 8, 2010

Shapercube batch 2 preparations and Batch 3+ stepper driver questions

Batch 1 is all sold out except our now almost completed photo model.

The prototype of the slightly revisited version 1.1 is on the way and will be produced in the next days.
Batch 2 will be shipped in week 19 and can be preordered already!


Future releases

After batch 2 is gone, we will run into the problem that the stepper motor driver 1.2 will be sold out. We don't want to support it any longer because it has too many components and takes too long to solder. On the other hand, we don't want to ship out unassembled SMT components to our customers.

A few thoughts about the options
  • The stepper motor driver 3.1 file looks good, except they left the opto endstop connectors out. This is an easy fix because all files are open source. However, the chip necessary on this board seems to be out of stock everywhere since months.
  • I can let produce fully assembled stepper motor driver 2.3 board now, but I don't have 3k+ cash spare (maybe anyone interested in buying a bigger part of the batch?)
  • I could let produce the stepper motor driver 2.3 boards and solder the SMT components in house. But I need someone who can do it my clumsy hands won't do well. [If anyone feels like he can solder 100+ boards at once with lead free solder, contact me.]
  • The polulu stepper driver could be an option. Problem might be that this chip needs heatsinking. Well I could try using the Shapercube frame for it. Question is: How long will their stock last? The A4983 chip is also nowhere in stock.

What do you think? Did I miss an option?

Thursday, March 4, 2010

Water jet parts

I got the first sets of 5mm water jet parts out of aluminium sheets. Previously we got the parts laser cut, but the cut was not straight and had far too many burrs.
For the first production batch, we get the parts cut by a water jet machine. On the water-jet machine, two sheets are cut at once. The tool head cuts the aluminium with a mix of water and an abrasive which is pushed out of a 0.8mm nozzle with 3000 bar.

The cuts feel a bit rough, but is much more straight compared to the laser cut parts I've got earlier.
However, the surface quality varies. Some of the abrasives will stick to the sheet.


For polishing, I got two polishing tools for my drill. I payed about 25 Euros for both.
The upper one cuts away a bit, the lower one is more for the finishing up. On small parts, it looks nice and almost consistent.
On the larger panels it's quite cumbersome because the drill is heavy. Unless I've something like a modified router to do this automatically, I can't add an option to polish the parts.

A possibility of getting rid of the bad surface is glass bead blasting. I brought a (useless) leftover part to a small sand blast shop nearby. The results are nice:

The surface is very consistent and a bit rough. Looks awesome, but has its price: A whole kit will cost 99 Euro more. Email me if you want to add this option to your Shapercube!

Tuesday, February 16, 2010

Shapercube coming March, preorders open


10 pieces of the aluminum RepStrap Shapercube and all of its parts are ordered by mid of March. The complete kit can be pre-ordered here.

The panels are water-jet cut and high quality and need very few post-processing with a file (less than 10 minutes), much better than our previous laser cut panels.

The documentation is stored in the Shapercube Wiki, which is currently filled with images and documentation, day by day.

Monday, January 25, 2010

Mendel Bearing Kit

While not working on a construction manual for our upcoming Shapercube release, we had some time making a new kit: The Mendel Bearing Kit. And the best part: It's only 29,79 Euro for 50 bearings in total!


Mendel bearing Kit now available on reprapsource.com


That kit contains 48 double-shielded 624 bearings and 2 double-shielded 608 bearings. All you need for one Mendel!