Monthly Archives: July 2014

Odds and ends…or Learning to 3d print by printing a new 3D printer #3

…arrived today. Namely linear ball bearings and linear rods. Printed one part of the motor_end.stl. The motor_end.stl is taken from the original Rostock Mini. No changes have been made on the Rostock Mini Modification (Sorry for not posting a link).

Still unchanged settings but I went back to the heated build plattform. The MDF is still as saggy as ever but yeah…wadeva. Though as I found out that propper cooling improves overall print quality on perimeters and stuff alike, too much cooling without a headed bed tends to warp corners. The more you cool the more they warp. So I had to revert to it. Lost some print area on the Y but I can live with that (2cm). As soon as my Delta-Rostock is finished this won’t be an issue. Note to myself: Get cheap local storage area for printer armada muaha MUAHAHA.

So, yes….one of the motor_ends printed yesterday. Came out nice and so I was able to assemble one pylon. Shiny…

Oh yeah and not to forget the new carbon rods. Though drilling the Traxxas by hand was not that of a good idea. Holes came out slightly off the center but there is nothing that cannot be fixed using some Epoxy.

Platform with attached carbon rods

Platform with attached carbon rods

Learning to 3d print by printing a new 3D printer #2

Just finished the platform for the modified Rostock mini.

The modded version has the hex nut notches switched on the sides so I reprinted it again. Though I think it would be possible to have used the vanilla part. Anyways. Printed this thing again with my speed settings and a 0.30 layer height again. Came out quite good.

Accidentaly the Traxxas rod ends arrived today (just in time) to be attached to the platform. Now this thing really looks like some useful part.

I still have to reprint the carriages as they were modded as well. Finished one though and served it it’s eagerly awaited rod ends. There you go.

Fibre rods still to come.
LM8UU still to come.
8mm precision steel rods just ordered.
Lasercut frame – budget depleted. Next month.

Learning to 3d print by printing a new 3D printer #1

How cool is that !

Now finally after three weeks I get the hang of it. While my very first print, a 2cm x 2cm x 1cm cube, was really successful (for a first print) I had to deal with lots of issues. More than the half of them had to deal with fixing, repairing and generally compensating someones elses inability to design a proper, (decent) working 3d printer. The other part was just figuring out the how slic3r works and which settings do best.

I had to deal with wobbleing on the X axis, wrong laser-cut parts, broken parts and clogged and jammed extruders. After all those problems were ironed out I finally got the chance to deal with slic3r in depth.
So this post will be about slic3r settings that work best for my TwoUp 3D printer.

Test object to be printed is the Rostock Mini. I thought, if I get this printer to work, the first thing one should do is print a new one. Actually this thing is not THAAAT bad. It just needs a lot of love and while working with it you realize what has gone wrong in it’s design process and on which corners money was saved.

The Rostock Mini is a Deltaprinter. They work totally different from the traditional XYZ printers but I guess a picture says more than 1000 words.

Rostock Mini

Rostock Mini

I started with the carriers. You need 3 of them so I started to print all 3 at once. I printed with the safe-settings suggested from the fabric8r.com forum. All speeds set to 20mm/s; Bridges set to 10mm/s.
The 1st layer was printed at 0.254mm. The subsequent ones with plain 0.2mm.
Infill set to 0.8 something. Did not matter that much.
External parameter first was checked.
All Acceleration values were set to 250mm/s.
Perimeters = 3
Top/Bottom shell = 2

When the print was finished I saw that only the carriage in the middle of the print bed had nice walls/perimeters. The two carriers in the front and the back had defects in their perimeters. I guess, this is caused due to the bed not being very stable when it moves to far to the Y-axis maximums. So for best results when using a OneUp/TwoUp just print in the center of the print area.

Rostock Mini Carriage

Rostock Mini Carriage

Center Print

Front/Back Printed

 

Printing without Retraction
The next thing to print was the extruder_v2. The Rostock mini is still tagged with WIP and I think I have read somewhere that the author is not very happy with the current extruder design. Further research has to be done. Same settings as above applied here aswell. Decent outcome. Additionally I printed the extruder again but this time without retraction to see how it performed. See yourself.

Left: w/o retraction Right: with retraction (1mm)

Left: w/o retraction
Right: with retraction (1mm)

 

Speed increased; External perimeters last

Next in line were the idler_ends. 3 of them again. Here I experimented a bit with speed, layer height and the perimeters.
The first idler was again printed with the above stated settings but with only 2 perimeters and 0.4 rectalinear infill. Took 3 solid hours and 47 minutes to print. Quite some coffee break…

1st print: Strong layer blobbing

1st print: Strong layer blobbing; 0.20mm height

 

For the 2nd I played around with the perimeter order. Until then I had always printed with the option “External Perimeters first” checked but on all prints I got those naggy blobs at the beginning of each layer. Like the extruder could not spit out the filament fast enought for its pace. Then I unchecked “External Perimeters First” and BAM I got very nice external walls. The blobby filament lines do still occur but on the inside of the layer. When it prints the external layers there is enough molten filament in the nozzle to print a smooth line. I also decreased the speed for the external layers to 50% (from 20mm/s) and the internal perimeters to 70%( from 20mm/s). Also I increased all infill speeds to 30mm/s and set the extrusion temperature from 200°C to 215°C. The infill came out very nice. No dirty lines. All good.

2st print: Medium layer blobbing

2st print: Medium layer blobbing; 0.20mm height

On the 3rd idler_end I cranked up the speed even more. 40 freaking mm/s for the infills and 30mm/s for the internal perimeters. External perimeters still on 50%. This reduced the printing time to sleeky 1h40min (roughly). To squeeze even more time out of the print I increased the layer heigth from 0.254 (1st layer) / 0.2mm to 0.3mm for each the first layer and the subsequent. The outcome was even better than the 2nd print. That is somehow paradox. Printing faster, with thicker layers gives much much better results. There is nearly none defect on the external walls and all the bridged wholes came out very nicely compared to the two slower prints before.

3rd print: Low layer blobbing

3rd print: Low layer blobbing; 0.30mm height

How awesome is that !

 

As I am writing this post I realized that the original Rostock Mini caused some issues as said by the author. It seems he lost interest in this project but luckly someone else picked up the plans and modified them for better results. Currently I am reprinting some parts as there were some small changes in the models. More print reviews are to come !