Arcol blog Just another RepRap weblog

24Jan/10Off

Going blue

Some diversity or how Latin says: Varietas dēlectat.
But the reason is trivial: I ran out of the white plastic.

23Jan/10Off

Mendel build progress — day 10

Not much things could I do. Im waiting for the machined extruder parts to arrive, meanwhile I mounted the extruder RP part on my Mendel to get a feeling.

20Jan/10Off

Mendel build progress — day 9 (updated)

Today I put the belts on Mendel.

19Jan/10Off

Mendel build progress — day 8

I designed a new drive-pulley. What was wrong with the old one?

18Jan/10Off

Mrs. Potts ;)

Last week our friends came to visit us and the lucky one could choose one thing to print from thingiverse.com.

THIS IS IT:

More photos after the break.

17Jan/10Off

Mendel build progress — day 7 (updated)

Today I cut to sizes all the sheets and also mounted the motors.

16Jan/10Off

Mendel build progress — day 6

Howto create PDF from qcad drawings

13Jan/10Off

Machine Calibrating

In this blog post we try to answer the question, what should be the layer height if the head speed is 16mm/s and the motor speed is 40rpm. So calibrating the extruder theoretically, rather than trial and error.

Since I had my printing machine I always had some sort of printing deficiency. I always suspected,
that I made my settings wrongly or didn't adjusted it right.

I asked on the forum how am I supposed to set my machine/skeinforge settings right, and I was told that I should follow this walkthrough blog post.
I tried it, but I lacked the proper tool to do it right. I only have an "analogue" caliper, where the accuracy in theory 0.05mm, but Im only able to read it reliably 0.1mm:

Following the above tutorial requires a digital caliper with 1 µm (0.001mm) measuring accuracy.

The idea, that a measuring is required, when we know every details of the machine, is rather strange. So I asked nophead, what is his method to adjust the settings right. He said, he calculates the layer height and does not need to do any "trial and error", like the above mentioned blog post. We exchanged some emails, and here it goes the explication (at least what I grok from it):

Filed under: theory Continue reading
8Jan/10Off

Mendel build progress — day 5 (updated)

This is just a quick note:
As others suggested in my previous blog post and also on the
reprap forum I swapped the following parts:

  • 2 z-leadscrew-base
  • 1 z-motor-bracket
  • 1 z-tensioner

Here is a picture after the procedure:

So everything looks right. The whole process took about 3 hours.

Here is a top view of the fixed assembly:

For reference here is the wrongly assembled one:

The bottom of the machine:

Also some closeup photos:


z-leadscrew-base and z-motor-bracket


z-leadscrew-base


z-leadscrew-base and z-motor-bracket


z-leadscrew-base


z-leadscrew base and z-motor-bracket (the other side of Mendel)


z-leadscrew-base and z-tensioner

4Jan/10Off

Mendel build progress — day 4 (updated)

It was a long, useful but first and foremost exhaustive day.
Here is the final result of the building:

In a nutshell I finished everything except mounting the motors, cutting to size the belts and all the sheets.
I haven't received yet the motors, hopefully I will this week.

I started the day by mounting the frame. Here are some 360 degree veiw pictures of the assembled frame:

After I mounted the y-bar-clamps:

Then I wanted mount the z bars, and I discovered the printed model has a flaw:

As you can see two holes are missing from the z-leadscrew-base. Here is an extensive forum thread about it.

And thats also the beauty of opensource. The broken part is already fixed, I only need to download it the new version from the svn and print the new one. For a quick and easy fix, I simply drilled the required holes.

For correctly setting the distances of the frame's threaded rods a setting jigs is essential. It is not important the distance between two corners is 247mm or 249 mm, however it is really important that the distances are identical between all corners. For this a home-made jigs is ideal. Here is a picture of mine:

As you can see, there is only two additional part (M8 big washers) required. The black threaded rod is the z threaded rod. It is long enough to check all distances.

The next step was to cut to length the bars. I bought the best available quality from the 8mm rod. That is, I bought linear shaft. It's a 8mm diameter rod for linear bearings, it is really tough.
So my goal was to have the least scraps at the end. So I optimized the cutting in inkscape.
Here is the result picture:

So from 5x2m length bars I can cut for 4 Mendel kit!

At the end of the day an another bug surfaced:

The lowest point of Mendel are not the four frame-vertex parts. The gears are lower and also all the z bearings too!

In the mean time I will put some books under the machine. This bug is yet to fix in the svn.

UPDATE: It was not a bug in the model, but in my building process. Here is a blog post how to correctly put it together.

Hope it was a useful blogpost for all of you.