Z Zero Idea

[bstern]

I am thinking of simplifying the start up and zeroing of my machine.

To start, I was thinking of placing a touch plate outside the cut area much the same as has been discussed here. This would be kind of a permanent reference point. After surfacing the table, I would run a routine that would start by using the normal Z zero plate on the machine bed to find 0. Then I it would go touch the reference touch plate and calculate the offset and save this variable.

Then, when wanting to zero the machine I could use one command to do a C3 to zero the table to the prox swithces then touch the pad and calculate Z-O and set it.

The main difference is that from what I understand after resurfacing the table others go and machine the touch pad to 0. My way would save from having to change bits to do that.

Also, I have 2 Z's on a 60" wide table so I could do one touch pad at each side of the table for each Z. It would also make resetting the air drill offset a bit easier. I could even go so far as setting a variable that contains the offset between the two tough points so after surfacing I would only have to reset one Z and be good to go.

Any input? Has someone already done this?

[propellers]

Bob,
I have done this for years. We use a Jig to cut parts and on each jig I have a touch pad. For each part from the jig I have added in the program a C3 command then Jog to the touch pad C2 and each time I have XYZ set for each part precisely.

[beacon14]

One of those excellent ideas that I've considered for years but never taken the time to do. One thing to consider is that the touch pad needs to be exactly co-planer to the table, which of course you can do by surfacing it one time with the 'bot, but it needs to be mounted in such a way that it can't get bumped or warp and loose its alignment.

[knight_toolworks]

I used a bar of aluminum and I put slots in it and bolted it to the table. after I surface the table I zero on the table bring the bit to the aluminum ban and use it to zero both sides of the bar. I also flattened the edge with the machine too.
this way my bar does not get eaten up every time I surface the table.
usually I zero at the surface raise the bit to the material thickness and zero again. that way it is always say 3/4" above the table.
8510

[bstern]

David and Steve.. The reason to use software to record an offset is that the plate will never need any adjusting. Its just a reference point.
After resurfacing you would run the routine that would record the offset between it and the table.

There after, the Z zero routine would touch the touch pad and calculate Z by using the offset. This is similar to you inputting the thickness of the Z zero tool.

The main benifit is that the touch plate would never need to be moved or cut.

[knight_toolworks]

yes thats not bad but figuring out the offset may be a pain. well it depends on how the plate is mounted. if you could get a depth gage between it and the table it would be ok. but it is not a big deal to move the plate and I know it is right on because it is touching the bit when I move it. I seldom surface my table so it is not an issue really. but you method may mean you need two zzero files and an extra c# file to run it.
for me the ruitine is great as long as I am zero'd on the corner of the table I type c7 and I get a jog to the plate zero in it jog to .121 zero ask the thickness jog to that zero and jog home.

[bstern]

Steve, figuring out the offset would be automatic.
Done just the same way as the drill Z offset is calculated automatically.
The routine would zero to the plate on the bed after surfacing the go and touch the pad, read the Z position and save the offset in the variables file. No muss no fuss!

For the second Z I would use a 2nd pad at the other side of the table. The routine would just go to the 2nd one and save a different variable.

I am going to get this done as soon as I have time. I will post the code once tested.

[wberminio]

BOB
Have you perfected your code?

I'm in the process of doing something similar for my machine.

Erminio

[bstern]

Erminio, I am still working on perfecting this.

My routine works well for transferring the zero offset. I still have some problems with accuracy of zeroing using the original ShopBot plate. It can be off by .02". This then transfer to the plate offset.

I need to write code to "Bump" the offset up or down by .01".

I am also installing some prox sensors so I can raise the Z and A to a known safe height before starting cal routine.

For me its awesome to come in, turn on the machine and hit the Cal button.

Raise Z and A to safe height
Zero X and Y of prox sensors
Zero A and Z off plate
Set Drill offset off plate.

I also am working on a A and Drill auto offset Routine. Just put round bar in Z and it goes to a hole in the plate and sets the offsets. Both A and Drill use through bore bits with pointed ends so they can be used if brought down to only using the very tip of the bit.

I am close to have all perfected.
With 3 tools to keep trac of, its the only way to go.

[wberminio]

Thanks Bob

Keep us posted.I have a separate z rod set up to
zero to table.
At present I'm using a method somolar to steven's.
C2 uses the z plate-C4 uses the rod.

Thanks for the response.always trying to improve on a good thing

Erminio

[Gary Campbell]

Guys...
Here is a version that I use to zero my cutting tool in the xy&z and set drill offsets for panel cutting. The corner zero zeros the x & y to my air operated fences for either individual parts or parts that need to be machined on the opposite side from the nested sheet. Flip Ops in SB Link vernacular.

http://www.youtube.com/watch?v=b7M1mMhOvr0&feature=channel_page
Gary

[wberminio]

Gary

is that Morris Dovey's super zero?

[Gary Campbell]

Erminio...
Yes it is. I mounted it to a piece of plexi so vacuum would hold it.
Gary

[wberminio]

Great setup,Gary