Saturday, June 26, 2010

New field of research

Today I started a new field of research dealing with the “cooling zone” inside the insulator and below.

What I made up was a heat shield. My theory is that we have been concerned with the heat within metals; I wanted to deal with the unseen radiant energy.

My first tests tell me I’m on to something. I seem to have blocked some of the heat from the insulator and created a new mess of Radio interference.

The once working temp system failed in reading and providing power for heat, frankly it went nutz. So its time to do a complete rethink of the shielding of the wires and retest.

Wednesday, June 16, 2010

Poor man’s enclosure

aka heated chamber, heated room

Another problem with ABS is the fumes. My Mendel extruder seems to give off more fumes than HydraRaptor's does, perhaps because the melt zone is much bigger, and the white ABS seems to smell more acrid than natural ABS. I did a build with a window open to get rid of the fumes but most of the parts then warped, presumably because there was no longer a buffer of warm air around them, but a cool breeze.

In an attempt to tackle both of these problems I built an MDF box around my Mendel.

In my case everything I’m working on is “experimental” and in the process of rebuilding. What was needed was a method to grow with my projects. The answer was simple. Build an enclosure out of clear plastic aka "Visqueen" film. Thick enough to do the job and hold up to use.

Lightweight, flexible polyethylene construction film offers economical all-weather protection indoors or out. Known as "Visqueen" film - a brand name, although this is a commodity plastic product.

Some quick thoughts/ideas:
1) Make a front folding flap and install a couple of magnets to lock the cover when U need it closed.
2) Your stepper motors produce heat, cool them and reuse the heat. Install a fan blade on the unused shaft side,FREE cooling/reuse heat. Many sub-ideas can come off this simple idea.
A) Like the back and forth of the stepper could be used to make a one way fan.
B) The free air movement can be used to vent out the fumes.

Give me some links with your projects off these ideas. Would enjoy seeing them!

Wednesday, June 2, 2010

Toothed, Bead ,Chain Belting …oh MY !

Since our quest is to lower the cost and improve operation of our RepRaps I felt the need for an alternative belt to what’s currently being used.

Long ago on one of my parts quests I picked up some “Diamond Braided Rope” as a possible drive belt or maybe used in an emergency to fix a RepRap. My belief now is that it’s a very good replacement candidate. The numbers speak for them self. I recently ordered Tooth Belting @ $1.81 a foot, plus shipping, taxes etc. The Braided Rope I purchased cost only $1.00 for 10 feet of the stuff.

Further, this might be a superior product for RepRap as seen in the general specs.
¼” x 10'feet
Braided for Strength
100% polyester strands
Resists rot, mildew, oil, and gas
300lbs working capacity

On the minus side that Red & White is ugly and changes to a V type pulley system would need to be made. It’s made in China, so maybe a pure color is sold someplace.

One feature I really like is that the material is very RepRap like. Looking at the pic you can see that the manufacturer hot slices the material for packaging. This is very advantageous for us. Using a hot means we can melt the polyester to any part we might wish. If we wish a continuous belt I would just butt the two ends together and melt them. If looks or an added protection is needed, then put the seal inside some shrink tube and presto you have a dirt cheap continuous belt.

Another feature: This is round material and therefore makes it superior in looping compared to toothed belts.

Where to buy? I purchased these at Harbor Freight Tools Item number 96186. Also sure these are available at other locations.