Wall straightness question on MV1200s

I am newer to the wire EDM and our shop has a Mitsubishi MV1200s. I am having a little troubles with my parts coming out square when working with tighter tolerance parts. If I cut a dowel pin hole typically it will have .0002 tenths of taper from top to bottom on a 3/4" piece of material however if I turn off power master and adapt control and I slow down the feed rate on the first two passes to .080 they will come out less then a tenth of taper. Another issue I have ran into is the only way I have been able to get the outside of my parts square to within a .0001" consistently is if I use the same method as I do with the dowel pin holes and I slow down all 4 passes (we do not have the fine machining option to allow more passes). I know there is more to learn and I'm sure there is a better way to go about it. my question is if there is any way to speed up the process by using an adjustment in the machine or even programming it differently then I have been. This is kind of new waters as far cutting gauges in our shop so if anyone has any insight on a different way to go about it please feel free to add to it.


In order to get the accuracy I have had to cut a test piece(typically about a .750" square), measure the walls, then manually move the wire to get the straightness I need for some of these parts. The material that is going in the machine is tool steel, typically A2 that is ground and indicates within .00005 once on the machine.

Thank you in advance for any advice

For the accuracy on straigh pieces must activate the option STRAIGH COMP. IS VERY IMPORTANT TO PUT IN YOUR PROGRAM THE Z1,Z2 and Z5. This Will move U and V axis automatically yo achieve the máximum straighness. Also VERY important to align the wire and do taper Z.

The option of straigh como is on Maintenance, switch screen me should be in the first one.

Regards.