Flattening the work table

wwheeler · Post by **wwheeler** » Wed Feb 06, 2013 10:59 pm

I found this web site where the gentleman has created a java applet that generates G-code to order for flattening the table. (milling it flat) While it won't help those of us with the all aluminum tables. It will help those with mdf tables

http://psychoul.com/cnc/how-to-flatten-the-cnc-table

sandra · Post by **sandra** » Wed Feb 06, 2013 11:34 pm

for the aluminum tables
there is nothing to stop you from putting a piece of MDF or other material on top the table then milling it flat.

if for example you know your going to be working with a 12x12 area for while
attach maybe a 14x14 sheet of 1/4 to 1/2 MFD or other material to the bed. then mill a 12x12 section out that is flat the you can secure your work to it.

essentially your making a squaring jig
so you do not have to do the whole table but you could.
it just becomes how to fasten work to it and you do loose some z travel this way.

i have a 2in work setting tool I am going to use to see how off my z is after i get the krmx02 back working after I just installed my dragon cable.

wwheeler · Post by **wwheeler** » Thu Feb 07, 2013 12:04 am

Well I provided the info for anyone that wanted to shortcut the system. I use a sacrificial board under work too.

I've been working my own version of a dust shoe using a 4 inch hose and my trial cuts have been a bit off. Also when we cut the dragon cable more often than not we would cut clean through the sintra and break pieces loose. Course we cut these before we had the Z probe upgrade completed.

So it got me to thinking about checking the calibration of the other axis of the unit. I know there is going to be some variances that will creep into the construction. I found this set of instructions for calibrating mach3 to the table (at least for x and y)

http://prodrawer.com/calibrate.html I'm going to give them a try see how close everything is.

Post by **msimpson** » Thu Feb 07, 2013 1:17 am

@sandra
Thats exactly what many do on larger tables.

If I know I am going to do a production run on something, I create a fixture. I add index holes so I can zero my machine to the X and Y.

I then machine out the locations for the raw stock.

For sheet goods I will add a larger surfaced waister board if needed.

alamorobotics · Post by **alamorobotics** » Thu Feb 07, 2013 9:00 am

That is pretty much what I did when leveling my bed.
http://www.krforums.com/forums2/viewtopic.php?t=1376

I still use a sacrificial board since I don't want to mess up the leveling but the MDF board itself could be used as a sacrificial board and easily be re-surfaced if needed...

sandra · Post by **sandra** » Fri Feb 08, 2013 1:14 am

thanks for the link here on the site. don't know if i missed it or don't remember.

one question i have is if you put a superficial board on top do you do anything to insure it still leave?

wwheeler · Post by **wwheeler** » Fri Feb 08, 2013 1:46 am

You can level the board by running the router across it taking off say one or 2 thousandths of an inch or until you can see cuts on every part of the board your project board is going to rest on. The Java applet I linked previously will generate a gcode run to do just that. Or you can just use your cam program to draw a box as big as the target area and then configure it to be run as a pocket taking only a bit off. Obviously not enough to go through the board.

alamorobotics · Post by **alamorobotics** » Fri Feb 08, 2013 1:13 pm

I just used Cut 2D and created a big square 1/8 deep, that is it...

I use the sacrificial board like I use to on the 80/20 bed, just put it under the material and clamp it down.
If I do engraving, I just put it on the bed...

It's a little bit of a hassle to use the holes and lock the T-Bolts but it's worth the effort knowing that the bed is flat.

/Fredrik