hey guys i have a vm1 and have been having trouble running some AL parts. my problem is that when i cut one side of my part and then switch it over to cut the opposite side (it should follow the path of the cut from the 1st side) it does not follow the original path . It looks like the part has been twisted . I have changed vises but that still did not fix it I have also check if the vise is square and it is.
OK, if you have checked the vises and the fastening of them, so what I'm hearing it's a machine straightness error?
Is it a flat mill operation or a edge mill operation ? Would be useful with a picture of the problem part, as my english are limited.
For flat mill operation error:
Have you put at indicator clock in the spindle, moved the table so to the center of table is above the spindle. Then touched one side (as far it goes) with the indicator clock and then turn it over 180 degrees to the other side of the table. Do this in both X and Y direction, you should not read more then 0,005mm difference / 100 mm length (full size of table would read about max. 0,035mm and 0,015mm difference in X and Y) More difference here and the column or spindle head are not perpendicular to the table.
Maybe you also have backlash in your axis screws ? There are rotary encoder feedback on these machines so if the screw have backlash the encoder still reads movement on the screw while table is still.
/Piobaire (also VM1 owner) :-)