Flip op miscutting

[Rob Davis]

We successfully were cutting flip operations a couple days ago. Then have been running a series of jobs without flip ops. Now back to flip op job and the X axis is off and flip ops are coming out wrong. See pictures. Y axis appears to be correct. You can see the dado is too long on one side leaving an extra piece on flip side and they are too short on other side. Or you can see the KD holes don't line up and are whole circles on one side and too short on the other. Off by about .125 (guess, not measured).
We did have an X axis C-marker error in recent days and would that require us to have to reset all the G52 fixture offsets?? This is the only thing we can come up with that would explain this.
And to clarify, when we do flip op on back side, we use G52 marker for the corner of the fixture, bottom left of the sheet. When we identify the sheet G52, we should be using the same G52 correct??? We are a YouBUild location and when our machine was re-configured for YouBuild, Jody created the flip G52 as #1 and the sheet G52 as #2. Why would they be different??
We maybe overlooking the obvious here but we are absolutely stuck.
Can you help?

[attachment=0]Flip 1.jpg[/attachment

[Will Williamson]

This is the kind of thing that only happens on the week end.
Go in there and make the necessary .125 adjustment to the axis G52 location and give it a try .

[Rob Davis]

ALWAYS on weekends and ALWAYS when you have a deadline to meet. I got so frustrated I just shut it down and will go back at it tomorrow afternoon.
I know we can make the adjustment but actually have 2 questions:
1) Don't we actually have to make 1/2 of the .125 adjustment?? Just checking my thinking.
2) Is this something we will have to do every time we redo the C-marker? Is that what caused this? If not, then what did we do?
3) should my flip fence offset be the same for back and front side of the sheet? Thermwood set us up for 2 different G52s and I am thinking they should be the same? If you do flips Wil, could you check your settings for fences and tell me if your flip and sheet fence offsets are the same G52?

Anybody?

[Will Williamson]

Yes I use the sane same fixture offset for both . I make a small cabinet 12 x 12 x 12 and use it to set up and test my results
i also make my own flip op fence 24" x 72" to locate to locate full sheets
and on the inside corner of the jig where the fixture offset is I locate a drill operation and when the machine goes to drill it gives me an exact fixture location.
once I have that number I change my offset until my tool lands in the exact spot I want it to
I only do flip ops occasionally but I do two sided cutting all the time
one more thought if you change your outline tool diameter your fixture offset location will need to be adjusted that could be your problem
call me if necessary 810 310 1111

[Rob Davis]

Wil, thanks a ton. New day, new perspective. My plan is to verify my fixture offset by locating a sheet and then going to G52L1 and see if I am correct. Then I am going to (I think) find that X axis is out by 1/2 of 1/8" probably from the C marker reset we had to do. Correct my offset in control, cut a set of 3 pieces using a scrap sheet and verify. If my G52 is correct, which I can't imagine, then I am going to fake it.

So what is the difference between flip operations and 2 sided cutting? When I say flip operations, I mean cut the back side of the whole sheet first, then flip it and do the front side and outline.

Thanks again for the help. Hopefully I can return the favor some day.

[Will Williamson]

Two sided cutting is when I locate dowels in my first side then mirror then flip the part in the software and drill my location dowel into the bed of of my machine
but that does not have any thing to do with doing flip op in ecabinets I went through the same thing the last time ai set up for cabinet cutting
I almost never cut cabinet parts
I have a cs45 so I have plenty of room on my table to change my fixture offsets to about 5 inches away from my G901 location
I not in the shop or I would send you my file for the flip op fence I designed but call me this morning
keep that outline tool diameter in mind it will change your fence location
Once I set my fence location I changed my fixture offset to match it

[Daniel Odom]

I try to keep flip ops to a minimum... actually I try to avoid them altogether if possible. But when I do need them I don't use the whole sheet method, I do something similar to what Will suggested only I screw down two 7" or so wide strips into an L shape on the edge of the x and y axis. Then I machine an L using cutter comp with the offset as 0,0 so that a part placed into the machined L fence is wherever the machine thinks the offset position is. Saves a lot of time and you don't have to worry about finding accurate numbers with the controller. This might not work well for whole sheets but works great for cutting dados for backs on a flip side of a part or placing a square part back on the machine and doing non-outline operations. I tried doing the whole sheet flips but always have trouble since the material is almost always warped on the side that makes it impossible to vacuum down

[Rob Davis]

Daniel, Flip Ops are the absolute worst and we avoid them like the plague. Any program we write has no flip ops. Unfortunately we didn't write this one but machine has done it before just a week ago.
Wil, I checked G52L this morning and all are dead on within 0.004. Outline tool is correct and diameter verified. got it all ready and should be good. Ran one part and BAD!! This is going to drive me to swearing and drinking. Have made contact at TW but they are not yet in. I will post the resolution when I discover it, even if it is something stupid I have done, which is highly likely.

[Will Williamson]

Can we post dxf files on here?
Daniel I keep a roll of clear packing tape handy and when ever I have an issue with warped material I run a piece of tape around the edge of the sheet 99.9 percent success rate

[Daniel Odom]

Cool, I'll give that a try whenever I get a chance, thanks.

[Rob Davis]

Problem resolved. Issue was ours, not Thermwood! Ever feel like choking your help??? Here is what I sent to Joe at Thermwood outlining the solution. One big lesson is to re-verify the G52 locations if you ever get a C marker error and have to reset the axis. I am convinced that is the start of this but it went on so long for our own stupidity!

I think problem is resolved. I write this with a lot of egg on face.(!) Based on the insistence that programs are correct, etc and had to be in the G52L1, last night I took my operator and physically watched him verify the coordinates of fixture offset. Turns out we found 3 things:
- Biggest problem was the operator was verifying the G52 location using a 3/8 tool and when doing the math was subtracting the tool radius of 0.249 creating the vast majority of the error.
- There was a small ding in actual fixture where it got dropped or something and while only a few thousandths, not helping.
- The C-marker error we had must require that we "re-verify" or recalibrate the G52 location. Supposedly we had done it multiple times but operator using wrong tool dimensions oddly matched the error we were seeing within reason. Any time we have a C-Marker error we are going to verify G52 presets in future.

We had to make a new G52 location and successfully made good parts.!@#$%^&*

Sorry for any hell we put you through for our own stupidity! But most of all thanks for hanging in there with us. Watch your mail for a thank you.