Friday, December 31, 2010

Willow Gets Some Dental Work

I started noticing that my round holes were not quite round, so I checked my belts and determined that the X belt was a little looser than I would like.  I tightened it and started printing again only to discover a horrible noise and  the x motor binding and skipping.  It happened at a few points across the bed but ran fine between them.  I looked around for the problem, what did I mess up by tightening the belt?

Broken Tooth

It turns out all I did was make an existing problem worse.  The x-axis pulley had lost a tooth.  For the looks of the hole where it use to be it had been gone for awhile. (Also note the wear on the teeth from the belt...)

Broken Tooth

Which explains some other strange x-axis noise I could not place.  Lesson learned "Listen to your bot!" if there is a strange noise look around more and look under things.

The easiest way to fix this, and keep my nice pulley, was to remove the pulley, flip it over, and put it back on.  Easier said than done...

Once I started looking at it closer I realized why the tooth broke.

Hollow tooth

Four of the teeth are completely hollow.  I am not sure what infill settings we used when printing the gears.  But the 4 that are are 45° from the infill direction have none in them.
I then became concerned about my other pulleys.  I checked and they all have the hollow teeth but Z and Y both have all of them still.  But I will have to keep an eye on them.

How to reinforce the pulley so that it won't break again?
It turns out the holes were big enough that some of my waste PLA (0.5mm) would slip down into them.
0.5mm waste PLA (for filling the void)

So I cut 4 pieces, mixed up some epoxy and glued them in.
Pulley with voids filled

Here you can see the reinforcement PLA inside the teeth.
Pulley with voids filled

I then pressed the pulley back on with a bar clamp.
Pressing pulley onto motor

Fixed motor

I then reinstalled it on Willow and re-tightened the belt.
Fixed motor

Back in business and printing again.  The x-axis is quieter now, which brings my back to "Listen to your bot!" if there is a strange noise look around and look under things.

A final thing to note is even professionally printed pulleys will eventually wear out.

Thursday, December 23, 2010

Willow gets a new light

I had a light I made using perf board that fit on the old x carriage.
Unfortunately it would not fit on my new x carriage, so I designed a board with KiCad and had it made using BatchPCB.
The idea being to have 4 different sets of 3 LEDs.   I chose White, Orange, Green, and UV.

The UV is very cool with the Ultimachine Blue PLA.

I originally designed it to have the LEDs wired in parallel but after getting the boards I realized that was a bad way to drive the LEDs so I changed the board by breaking a few traces and adding a few jumpers.

Saturday, December 18, 2010

A Holiday Prusa Mendel

I found and the novelty of this holiday remix of the Prusa Mendel was enough for me to try printing one.  Kliment is making a holiday themed build plate for each day starting on December 2nd and ending on the 24th.  You can print one plate each day and will have a Prusa by Christmas.

All parts through day 18

I have pictures of all the parts I have so far here.

I like the simplicity of the Prusa but am taking a slightly different approach to RepRap simplification with my Integrated Parametric RepRap  (more on that soon).

Sunday, December 5, 2010

More Plastic, a Fourth offspring, and an update to IPR

I used the money I made selling my first three Mendels to buy more PLA from Ultimachine.  I bought 2 rolls each of Green, Blue, White, Silver, and Black.  Someone that I met at Metrix: Create Space is buying one roll of the Green from me.
Willow is happily restocked with plastic and the Green was used to finish a fourth Mendel set that will be listed on eBay in the morning.


I also made some progress on my Integrated Parametric RepRap work and posted a new version of the OpenSCAD files on Thingiverse.