Wednesday, November 9, 2011

A home of its own.

Well, I finally got the spare cash flow to order the rest of the power train components for the CNC. I picked up the couplers, shafts, and collars from Ahren at CNCrouterParts. That dude is fast. I emailed him a question and within the hour he had replied. I ordered the gear from him and it was at my house 2 days later. He is legit and a great person to do business with. I also got some astounding service from McMaster. I ordered the ACME rods from them and they were on my door step the next day. Crazy stuff compared to some of the other troubles I've had in the past from other companies.

I went over to my Dads shop to get to work on the power train and ended up building a rolling cart from random scrap pieces of building materials he had laying around the shop! As you can see I've found out you can post pictures beside text. So enjoy this new feature! Any way. There it is. Its held together with what I would call sewing needles (air-gun "nails") and glue. ;-) Its on wheels so its easily movable and once I cut some slots out in the faces of the cart it will be able to hold the electronics pretty well. Unfortunately, building this also means that I didn't even touch the CNC other than to pick it up and put it on the cart.  With classes coming to an end I'm going to have to hit it hard to make some free time to finish this up.  As I sit here and type this post Ive got 52 days 10 hours 40 minutes and 5 seconds...4 seconds...3 seconds... Its coming up on the CNC deadline.

That brings me to my next point. What is finished? Where is the line? I'd like to define that. The end goal is to have a working CNC machine....and something cut from said machine. I want to start the 2012 with a working tool that can be used to take a drawing and translate it into a physical piece you can hold in your hand. With the current hardware I think I'm going to be limited to circuit boards and 2 dimensional objects  due to some of the limitations of my driver setup and the gcode interpreter. We'll have to start there.

What's my hardware setup? Fair question. I think I may have alluded to it in the past. Its another DIY project I did in the past. Its troublesome...its unreliable, Its even ugly but I built it. Its a trio of reprap driver boards that I learned to make using solder paste, surface mount components, and an electric skillet. Yeah it worked great. Really. Anyway the thing is that there's a bunch of wires coming and going from each of the drivers to a boarduino (also a DIY project. First thing I ever soldered). It needs to be cleaned up and wire managed. Currently its all mounted in an old PC case. It ran one of the previous CNC machines I attempted. When I say "ran" I mean that very...very...very loosely. I was able to feed the boarduino a single gcode command through a terminal and it would execute it. Above that things would go wrong instantly. There were timing issues, wiring issues, and above all the screws were just that. They were threaded rods from lowes. The would bind and get all kinds of messed up. Ill try to pull a picture of the one thing I cut with it. Its just a couple of lines in a piece of MDF. I use it as the picture for my Dad when he calls my phone. He takes time out of his life to help me with these projects so I figure he deserves that.

Moving on past that learning experience. This time I have real ACME rods and legit hardware. Things such as helical couplers and thrust bearings.  Things that I couldn't afford back in the first two iterations of this project. Ill end the post with this.

Precision isn't cheap and no amount of engineering and creativity can be substituted for a well designed part. Sometimes you have to bite the bullet and buy the $20 dollar couplers or the $30 dollar carriages rather than trying to engineer your own.


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