Adjust trunion table or can solidcam do it?

[pinguS]

Hi all,

Here's one someone may have already asked, maybe not, or maybe no one has ever had this problem.

To start with I have a trunion on the mill which when you move 90deg, the table drops 90deg to the left, i.e. in the x-.

So if I program a part in Solidcam which starts with:
1. table upright, drill a hole in X0 Y0 (center of the part/rotation)
2. then drop to 90 deg, (which makes the part move around 150mm in X-) and drill at lets say X-125. Y0.
3. Then take the part out and inspect it, I find the hole in 90deg is actualy in the right X position as programmed X-125. But the Y is Y-0.2 (ish)

No what I as wondering, without having to undo the whole trunion table and try to realign it, (as it is out of position by maybe only 1/2 degree), can I put this adjustment into solidcam.
p.s. I have tried to set my 2nd machine reference point at Y-0.2 in Solidcam, but the Gcode obviously output is Y0.2 as the computer doesn't know there is a misaligned table in play.

What do most people do, do they physically adjust the trunnion, OR after a sample piece, just adjust all the Home Positions on the actual machine OR have you done something in Solidcam to adjust, like the GPPfile??? On my part if I drill at 30 degree, the Y0. position measures about Y-0.08 ish (just a tangent of the table angle I suppose)

PinguS

[MKproto]

Unless you can adjust you home position to be just like your table I would realign the table. a 1/2 degree is huge amount to be out (imo). You will save yourself alot of headaches and bad parts in the future if you set the machine up right. You could get your post modified (if you have macros, and are only doing positional work) to add shifts that you can manual move holes features back into position.

[Brakeman Bob]

I agree with MKproto, you are only storing up trouble for the future by ignoring table misalignment.

[pinguS]

Ok maybe 1/2 degree was an over exageration, when the part moves around 175mm when rotating the B axis 90 deg, i.e. 175 mm to the left, then the alignment measures about 0.09mm out.

Very little, but never the less, whats the easiest way to realign the table as every time I start to tighten the bolts, is moves again (ever so slightly), I'm sure you guys have had this before???? Maybe I should really post in another area of the forum!!!!

[Brakeman Bob]

Is your table not tenoned to the machine table? If taking the 4th axis off and on is a regular thing see about making a sub-plate that has accurate locations to the machine such as tenons or JIS edgeplates, then set your 4th axis up accurately (3 microns over 300mm is normally acceptable) and drill & dowel it to the sub-plate.

To overcome the table moving when bolting down (a) tighten down in stages using a opposite hole pattern (like tighening down a cylinder head) (b) tram a DTI up and down the reference edge in between stages and (c) use a plastic shot mallet to make minute adjustments to the table alignments at each stage. The last sounds brutal, but it is tried & tested (mind you, do mind where you tap it - as low as you can get on a nice solid bit); a fellow I served my apprenticeship with possessed much finesse and I witnessed a "2 tenths" tap many a time (those were tenths of a thou' not tenths of a millimetre)

[pinguS]

To be honest, never heard of these types of plates, as never used the milling too much. Do you have a picture or maybe even a simple cad file of something that may be useful, which I could modify to suit my machine????

Or a website which may be helpful??

[Brakeman Bob]

In your machine manual there should be a pallet or table application drawing for your machine. A sub-plate is simply a flat piece of steel designed around the precision locations detailed in the application drawing that has (equally precise) locations for the fixture mounted on it.

[pinguS]

Yes, I was actually referring to Tenons or JIS Plate, is this just another word for Sub Plate.

Either eay I have taken the drawings out for table locations, I checked the 5axis unit, looks as though it only has 2 bolts to tighten, am I missing something, maybe a bolt or 2 !!!!

[Brakeman Bob]

Tenons you will find in the Wixroyd or WDS online catalogues; for the JIS edge finder, that only applies if your machine has it. Look for some M16 holes on the vertical edges of the pallet, 2 holes on one face and one on an adjacent face. Their dimensions are specified in the JIS standard.