Virtual Leveler

[steven_seim]

Greetings. I have a suggestion regarding an enhanced table base coordinate system.

I built a hydraulic steel frame for my bot, and I use a laser optics bench as the working table. I can raise the table such that it touches the bot frame, and/or can be lowered to the floor.

Careful as I was to machine and level the frame, I still want that last 5%.

I would like to suggest a virtual leveler. Give me a keystroke combo that prompts me to touch the table at all four corners of a projects working area. This area could be the entire table or just a square foot. I'll have my keyboard with me, and use the arrow keys. I'll put a 1/1000 brass foil shim on the table. When I cant move it, thats the x,y and z limit for that corner. Repeat for the remaining three.

Presto! I have leveled the table and set the working limits.

If this message is inappropriate I apologize.

If this can already be done with combinations of VL, VA, ZT and the like, I'll figure it out by cracky!

[roney]

Steven,
By cracky is it...with all due respect, I'm not quite as impressed with your leveling scheme, since you can insert a 1" flat-bottom cutter and run it back and forth (via a file)to level the sub-table, as I am with the description of your actual table...sound pretty wild!!! Got any pics?
jrc

[Gerald D]

Hi Steven

I like your lateral (level) thinking! Roney is right if you want to level the TABLE, but sometimes we need to level the reference surface of the object to be machined. A very simple example: We cut small wooden signs with a V-cutter, where the depth of cut produces the "fatness" (width) of the letter strokes. When a customer brings us his favourite bit of old oak, it is often warped and we can spend a lot of time trying to pull it down flat. Your "virtual leveller" will help here.

The brass shims often referred to on this forum, are electrically connected to the spare inputs on the SB. (Simply testing if you can move it by hand, is more economically done with a bit of scrap paper)

[rgengrave@aol.com]

If you use any wood top? you will not get a level table. wood will move with any weather, I day level, the next day not, then again level, if man can bend light, then weather can bend wood, just look at it as a raised panel door, it will bow if it can't move, sheet metal will shrink .00010.02 with heat at 98.2 degree, lead .0001.0 at 87.2 and copper .00001.02 at 56.7, and wood will be .45.04 x 6 times that amount at any temp above 67.3
Nasa 2/6/53 and Nasa 9/6/99

But for a shopbot this is just right if you do not sweat while cutting.

Ron

[oneyra]

Yes Ron I agree with you 100 percent,
therefore our warranty of 30 min. or 30 ft. which ever comes first. It also helps to turn off most of the lights in the shop while showing the finished product.
Man, there I go giving away trade secrets again...
crj

[rgengrave@aol.com]

I new I was doing somthing wrong by leaving the light on..(-:

Ron

[Gerald D]

Ron & oneyra, I don't understand your brand of "humour" - would you guys care to comment on how to deal with distorted surfaces that cannot simply be skimmed flat?

[rgengrave@aol.com]

Gerald all I meant was if you have a metal surface instead of wood? you will never need to relevel.

Ron

[Gerald D]

Ron, I get your point now. I am a "metal" guy by profession and I know of no economical way to build a flat steel table suitable for a SB. Welding stresses cause distortion, and even the sun shining on one end of a table could have the same effect (realise here that I am talking of sheetmetal tables - not heavy cast iron or similar).

The ideal, economical way still appears to be a strong steel sub-frame, that can be welded without too much concern for flatness, covered by a renewable wood top that can be skimmed from time to time.

[rgengrave@aol.com]

I was looking at a cnc table at Ford Motor Co. last summer when I visited my buddy thay runs the cnc machine, they have a metal table with panels, the panels look like 1" solid wood? there were 6 panels, the panels just layed is slots.

He said this seemed to work the best because it could breath better and not warp,When i build my new metal table I think I might just try this.

Ron