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Topics - jaideepshinh

Pages: 1
General Mach Discussion / Homing accuracy
« on: June 30, 2014, 01:30:12 AM »

I'm somewhat new on this forum, and may be posting this in the wrong section- Moderator, please put this into the correct section.

A little background information to my problem: I've done a retrofit for a 3 axis machine (A beaver NC5, originally on a Heidenhain TNC 355 when i purchased it) with a Mach3 system. The system i've built has the following configuration:

1. PC:

AMD Phenom 2x4, 920, quad core running at 3.2 Ghz (i think- don’t remember at this point), with 4gb ram, a graphics card, SSD and 1 lpt port (all well above the min requirements)
operating system: Windows 7 x86

2. Servo drives:

Sinamics V60 series, 6NM torque- 3 sets

3. Modbus device:

ABB AC500 series PLC, with approx 96 IOs (including 4 Analog out and 2 in). PLC program takes care of most of the machine functions and safeties, as i, with all due respect, do not trust the mach3 brains system from my experiences in building this machine.

This is for a 3 axis machine with ATC, and has a number of sensors and feedbacks, hence all the IOs.  The machine is in good condition mechanically; with guides being quite fresh (the machine wasn’t used much and was a demo machine at a college. This is the second retrofit the machine is going through- it was originally a NC machine)

Now the problem i'm facing is that the homing reference accuracy isn’t good. The Heidenhain system, with the same switches, had fantastic home reference accuracy (to 10 microns or less- we never had to pay attention as the surfaces generated were always matched). The machine would home in what appeared to be the same fashion as the Mach3 system.

However, the Mach3 implementation is a slight tragedy in comparison- the repeatability of position after reference is not worthy by machine tool standards. Now the limit switches are the same as earlier. The ball screws are the same as earlier. The components which have changed are the motors, servo drives, controller and electricals.

In order to solve my problem, I’ve done a little homework on how the other controls reference their axes, but will post that afterwards after receiving some ideas back on this forum.  Posting that now may turn the conversation in a direction which I would prefer to avoid at this moment.

Now, for my understanding, how accurate is the home reference for the others on this forum?

The homing accuracy is of very high importance to me as we have frequent power outages in the place where I am, and a system which loses position in the process becomes extremely tedious to run.

With best regards


Pages: 1