Cut Inconsistency or Table?

[Leo]

Or the spoilboard alone could just not be flat as Leo suggested.

The OP stated that the spoil board was previously surfaced - I believe it was as flat as it could have been.

[GraClay]

I'm assuming the spoilboard is MDF and you are using a vac table. When you surface plane a porous surface such as MDF there is no guarantee that it will vac completey flat as air is passing through the spoilboard. i.e. in some areas the spoilboard can be sitting slightly above the vac table depending on your setup. So after you have planed the surface you then place a non or less porous material over the spoilboard and vac it down except now the vac will pull the MDF spoilboard down thoroughly as you have a non or less porous material over it i.e. the substrate you are cutting. The result is that the top of the spoliboard is no longer at the exact same height as it was when you planed it. Hopefully that makes sense.

No if you don't have a vac table then good luck as you are not likely to ever plane it flat if there is no vac to pull it down.

Note: MDF changes thickness depending on the weather. This can happen over a period of only a few hours. I experience this almost daily in our hot & humid summers and it is particularly noticeable if you are fanatical about keeping your spoilboard in good shape. My goal is to never bite into the vac table more than .2mm which is around 8 thou in the old speak.

Note 2: My spoilboard starts life at 16mm thick (I think around 5/8"?), is screwed down to a vac table that already has another 16mm MDF panel over it (also screw fixed) and the current spoilboard has been in place since around 2008 give or take. It is still at least 10mm thick (3/8") and is probably due for replacement as I have penetrated by around 3mm a couple of times. Human error.

[knowlzy0791]

Sorry it took so long to get back to everyone.

I surfaced the spoilboard on both sides. I ran a program setting the Zero at the spoilboard surface and seemed to get a more accurate cut depth throughout the sheet.

So my question now is, since the Z axis is Zeroed at the material surface which should be the same throughout the sheet. I should only have to re set the Z axis Zero when I switch to a different bit. The old motors and program utilized a "push pad" (not sure what it is actually called). It is a plunger that is attached at the end of the router bed. The new program does not utilize this so I still have to set zero on the spoilboard, which would cause me to move the cutting material which would move my X and Y zero points if it is not moved back exactly where it was.

Is there a way to set the "push pad" back up in the Mach 3 software so I can just have the new bit tell the machine the length of the bit with that?

I switch in the middle of programs quite a bit because I use an edging tool and a cutting end mill in the same program a lot, it is a real hassle since they are different lengths and until I switch a few times and memorize the depth different I am constantly having to manually change the Z heights and it causing an inconsistency and takes time.

[martin54]

What you are looking for is an automatic tool height setter, you may be able to utilise the original pad but would probably require some rewiring as you will need to use a machine input for the pad. Can't remember if the default mach3 screen set has a tool height setting function so you may need to invest in something like the 2010 screen set or the big tex blue screen set. These you will find on the mach support site & are about $20 if I remember correctly.

[knowlzy0791]

I contacted MachMotion support, hoping they can understand what I am after and help out.

Thanks everyone for the input, it is much appreciated!