Tuesday, March 29, 2011

A Look at the Microcarve A4 CNC

My Microcarve A4 CNC is on its way! John shipped it this morning.

Here's what it looks like:

Over-all view


X Axis Motor Mount at Left


Y Axis Motor Mount in Foreground


Z-Axis. Beautiful, isn't it?


Its Unpainted Twin. A bit more detail visible.


Logo shows nicely here.

I'm getting ready for its arrival by putting together the electronics. I'm modifying an old UPS cabinet for the motor drivers and power supply. Pics soon.

Monday, March 28, 2011

CNC Machine: Microcarve A4

I've been looking at setting up my own CNC machine for about ten years now. I've worked with CNC and CMM machines off and on since the early 80s. I remember hooking up a CP/M computer to a CMM machine, wowing the lab with its ability to automatically record measurements then produce a compliance report on each part as it was inspected. The next day we went back to doing it manually. Everyone was impressed, but they weren't prepared to add computer infrastructure to the lab at that point.

In my case, I wasn't looking to add supporting a CNC machine to my workload before now. Whenever I read the online forums for adding computer control to milling machines, or building up simple hobbyist CNCs, it looked like working on the CNC itself became the prime object of the effort, rather than using the low-cost CNC for production.

There are a lot of bits and pieces to a CNC. There's also a lot of work represented by the physical machine's construction. I'm aware of this from the professional CNCs I've seen at work. They're high precision equipment, with a team of skilled people supporting their operation. Like a machinist, a machinist's assistant, an electronics tech, a programmer at least part time, and a metrology tech or two checking up on it periodically.

As a hobbyist, I have to do bits of all their jobs, plus the jobs of the design engineers, manufacturing engineers, materials engineers, and their technicians to produce things with a home CNC. Needless to say, I won't be trying to do quite the same thing.

I've started by purchasing an existing CNC machine bed rather than trying to design and build my own. I'm also purchasing a commercial motor controller system. My engineer ego is not in the least bit challenged. My engineer superego knows well the tremendous value of the design work that's gone into the pieces. Cookbook integration is good enough for me here. It's the stuff I make with it that I'll set my ego loose on.

The machine I've purchased is a Microcarve A4. The designer did the commercial Fireball V90 previously. The Microcarve A4 is a smaller unit built for high precision. Which suits me perfectly--a specialized machine is just what I'm looking for.

The controller I've purchased is the Gecko 540. It looks like a well integrated unit with a lot of design fine-tuning in it.

Both should arrive soon, the controller (driver in CNC terms) may come tomorrow if the USPS package tracker is telling me what I think it is. I've got a computer running EMC2 that I've been learning how to use to some degree, that I'll hook up the Gecko and motors to once they're here to shake out that element.

I've got some decent software for 2.5 dimensional conversion of images and such (including the image to gcode software included with EMC2), I'm still trying out CAD packages for real 3D work and CAM programs for converting those designs to tool control instructions on the CNC machine. I want to get that all shaken out to make for as little obstruction between idea and finished part as possible.

It'll be an exciting next couple of weeks. I'm looking forward to getting things assembled, functional, calibrated, and churning out parts. With breaks for infrastructure work (like dust/chip collection and an enclosure) between production runs..

Sunday, March 20, 2011

Don't Let La-Z-Boy Re-Pad Your Chair

My spring break project this week has been redoing the padding on my easy chair. I've got a great big La-Z-Boy that I bought about 10 years ago. The padding on the seat and the lower back needed to be refreshed and the time off from teaching this week gave me a chance to do it.

This Time, I'll Do It

Normally, upholstering is not something I look to do as a pastime. But, some time ago, I made the mistake of taking it to the La-Z-Boy factory to get the job done. The chair is one with ten massage motors built in. I often get tears in my back muscles, those motors are really important to me. When the chair went in to the La-Z-Boy shop, all ten motors were working fine.

When it came out, only two at the top of the back worked, the two most useless motors (from my perspective) in the chair. None of the others functioned. Needless to say I was pretty upset. La-Z-Boy not only couldn't account for the problem, but refused to do anything about it. It wasn't part of the service, apparently, to make sure your chair wasn't damaged in the course of repadding.

Not only that, but the new padding job was pretty lousy. It was only a couple of weeks before the seat was mashing in again. Plus, everywhere they had lifted up the upholstery there were now lots of sharp little staple heads. Before the heads had either been placed better, or hadn't protruded from the fabric.

I've been getting along with a small pillow and a scrap of moving pad to make up the difference until I had a chance to spend the time to fix it myself. Now I can see what La-Z-Boy really did for me.

When they opened up the seat to put in the new padding, they cut and tore the cabling to the motors. What they didn't get with a knife in the first pass, they just tore by yanking. Real sweet. Next time I want this sort of service, I'll put my chair in the driveway with a "Please Vandalize" sign on it. The same was done inside the back, somehow they missed two of the cables.

The new padding was just as good. A folded over piece of cheesy, low density "egg crate" style foam was shoved into the seat and the back. None of the old crushed-down foam was removed. Needless to say, no accommodation was made for the wiring.

For some reason they opened up the upholstery on the sides of the chair as well. I have no idea what they were up to there. Pushing out the sides to make the whole chair look more puffy? I have no idea.

So if you've got some La-Z-Boy furniture, do yourself a favor. Don't take it back to their factory for work. It's a rip-off. Chances are you can find a small upholstering business nearby that you can hold accountable for the work, so even if they mess up your furniture, you'll have some recourse.

Rolling My Own

I've finished the seat now, and repaired all the wires to the motors. Fortunately, only the wiring was damaged. It took me most of an evening to go through, test each motor, and get it hooked back up to the correct position on the motor controller.

For the padding, I removed the crappy eggshell stuff (it was dirty looking, and even though it was shoved in under all the other padding that was in the seat, it smelled pretty bad, like hydraulic fluid.) I cleaned up the padding that was worth re-using from the original stuff, put in some new stuff where necessary. I added a layer of the fiber material that lets the fabric breathe just under the fabric.

Last night I got the seat back in, it feels much better. Sewing things back up was a bit of a chore, but the results are worth it.

The back is still waiting for me to repair its motors and update the padding, but it'll be a lot easier to work with.

Tuesday, March 1, 2011

Model Railroading: It's Baa-aack!

Model Railroading is a hobby that's been at the edges of my life for a long time. And now it's entered from a new direction. But first to recap:

Round 1

When I was a kid I got interested in model railroading early on. As it was, I loved trains, and I lived in a train town. Even at 3, I was drawing my own trains with such detail that my mother had to look at the real thing to see what all those details were that I was drawing.

The idea of owning and running my own miniature railroad was certainly appealing.

But, we moved around a lot and model railroading was not an inexpensive hobby. I managed the next best thing in the way of hobbies: electronics. I built a crystal radio (and used it--a lot), and built circuits on those 50-in-one and 100-in-one kits.

Round 2
As a teen, I got interested again. I had some income and I got a starter set with a locomotive, some rolling stock, track, and a transformer. It was N scale, perfect for an apartment dweller. I built up a setup, some scenery, and had fun with it. But for too short a time. It was enough to get engaged, but not really to get deeply involved.

Various things got in the way. Fortunately, electronics still fit into my life as a hobby.


Round 3

I was grown, married, and had kids. What better time to start a new set-up? I still had some of my N Scale stuff. I bought some wallboard, cleared a desktop, and started work on the layout. I laid what track I had out on the board, intending to build up as I bought new parts. For now, I'd get a train going around with a couple of buildings to amuse the girls and let them see what we were up to. We managed this much, but then...

The garage where I set it up is also where we let a couple of our cats sleep at night during winter (they were outdoor cats.) They decided that the train set was "contested territory", and decided to claim it in the destructive method that male cats have. Fortunately the transformer, locomotive, and stock were all packed away. But most of the track was rendered unusable by the, um, corrosive fluids.

I planned on setting up a new layout with a cover over it. But other projects came along, and time slipped away. For about ten years...

Something New

Last night my younger daughter finished her homework, and we both had some time to kill. I fired up YouTube to watch some model-making videos. She asked to watch model railroad videos. So we watched a couple of things about making layouts. Which I roundly criticized, since I hate styrofoam and that was what was being used in these videos (yeah, I can understand why--I still hate styrofoam.)

Then she let me know she was interested in model railroading. She still remembered that short-lived setup we'd done together before the cats got to it. And she's looking for a crafty outlet. The more she learns, the more interested she gets.

I gave her the run of my small model railroading library (a collection of old N Scale and HO scale books like N Scale Primer and 101 Track Layouts). Today we stopped at Nor-Cal Train Shop after I picked her up from school so that she could see what it'd cost to get her own starter set. She talked with Jimmy there for about an hour and a half.

I guess she's interested.

He sent her home with a couple pieces of track and a couple of pieces of rolling stock to keep her inspired, as well as some magazines she's been reading all night around housework and homework. I've promised to move a file cabinet out of her bedroom that my wife and I left there after using it for a computer room years ago, she's trying to figure out how large a set up she can start with, and planning out ways to earn money to pay for the starter set so she can start operating something.

Her real interest is the modelling, though, it seems. Scenery, buildings, basically building dioramas with something that moves in them.

To tell the truth, I'm pretty surprised. This has all been rather sudden, for me. I wonder how long it's been percolating?

She seems committed. Telling her she couldn't just use my stuff, but had to buy her own hasn't deterred her. It'll be interesting to see where this goes.

Model railroading is a neat hobby. As I've learned, even if you don't end up doing much of it, the skills you learn from even doing a bit of it can take you in a lot of directions. I suppose I could say I got an early lesson in digital electronics from figuring out how to wire a reversing section in a track layout.

On top of that, I'm beginning to wonder what I could fit into a really small layout myself...with microcontrollers, of course.
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