Number 9 – Amorphous 3 ½ X 6 Precision Table

[Clockwork]

This is my ninth CNC project. Started thinking about building a large format table three years ago. It’s status has moved up and down my priority queue many times - I’m finally ready to begin construction.

Everyone has unique ideas regarding how to proceed with CNC projects. My design philosophy stems from the guy who sold me my first CNC components. He was a Manufacturer’s Representative for Parker Daedal. He schooled me on the benefits of using manufactured linear actuators as compared to creating the equivalent function from individual components. It is very difficult, if not impossible to match the precision in a home workshop. Also, the cost of the used Ballscrew Actuators he was selling me was less than the cost of the sum of the individual components. It all checked out and my head has been in that space ever since.

I tagged this build as Amorphous as its design has morphed many tens of times as various deals became available and were either accepted or rejected. There was no original plan. The final plan was determined by the results of a three-year scavenger hunt.

My design philosophy hit a brick wall when it came to the long axis on this machine. Couldn’t find long linear actuators for a reasonable price. I investigated developing a R&P setup for the long axis, but after working exclusively with Ballscrews it just seemed like a Rube Goldberg solution. Within the last month I came into a fantastic deal on a couple of actuators with six feet of travel. Not the eight feet I was originally shooting for, but it will accomplish everything I have on the drawing board.

The machine frame will be constructed from 8020 aluminum using Anchor Fasteners wherever possible - minimal use of joining plates.

Stumbled into a fantastic deal on 8020 stuff. I purchased 3 machines that were decommissioned custom configurations from a local aerospace contractor for a little over the scrap value of the aluminum. All of the high dollar motion components had been removed, but all hardware and even some E-Chain was included. The machines yielded about 500 pounds of series 15 and 40 T-slot stock. I disassembled the frames and had the hardware unsorted in boxes out in the barn. I brought the boxes in this week and sorted the hardware out into categories to understand exactly what I had. Started adding up the numbers and the value of the hardware alone is over $1500. (Wow) The bulk of this value was in Anchor Fasteners, about 350 total.


Here are the specifications with what I have so far:

Table
4’ X 8’ with a 3 ½ ‘ X 6’ cutting envelope.
Z Axis Travel – 6”

Resolution (With 10X Microstepping)
X Axis – 2.5 Microns
Y Axis – 5 Microns
Z Axis – 2.5 Microns

Repeatability (From Manufacturers Specs)
X Axis +/- 3 Microns (Kurota)
Y Axis +/- 5 Microns (Danaher Kollmorgen)
Z Axis +/- 1.2 Microns (Parker Daedal)

Motors
X & Y Axis – Applied Motion Nema 34 1693 oz in
Z Axis – Keling Technology NEMA 23 283 oz in

Motor Drives
Gecko G203V Vamps

Computer Interface
Gecko G-Rex via Ethernet

Manual Controls
1. Fixed panel with Joystick and Arcade Switches
2. Wireless Pendant

Power Supply
Three Acopian 24V @ 17A supplies wired in series to produce 72V @ 17A
This effectively creates taps at 24V and 48V for logic and future needs.


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[OCNC]

Awesome scavenging!

Chris

[harryn]

Nice Project start. I wonder if it is feasible to construct it in a way that lets you use your existing parts to make a 6ft table, but still allow a rebuild into an 8ft capacity table down the road ?

[remskm]

Just curious and if you don't mind me asking - what did the pair of six foot actuators cost?