Project Lead: Eric Mosley Assistant: Michael Logan

December 2013

• Roller Conveyor not aligned with saw table.

• Saw table was not trammed. (square in all axies)

• Saw was down.

Due to:

• Electronic issues.

• Software issues.

• Wiring issues.

• Firmware issues.

• Mechanical issues.

BEFORE AFTER

This was resolved by levelling the saw and machining a new improved mount plate for the roller table.

Machined a new mounting plate that would allow the conveyor

structure to be adjusted higher, so that the roller could be leveled with

saw table top.

New mount plate allowing roller height to be increased where previously it could not be.

BEFORE AFTER

Resolved by rotating the machine and locking its position.

Catastrophic issues with machine across the board.

At Power up the screen would display we had a catastrophic error. (image on the right)

My attempts to clear the errors were successful by reprogramming the CTC registry file. (e-stop was still an issue) But once power was cycled, all data / program was lost. Resulting in the same error screen at each machine power on/restart. The issue was caused by a bad CTC (PLC CPU) according to Joseph Machine. They said we would need a new CTC at the cost of $3700.00.

The CTC was repairable but expensive and we would be down a minimum 3-4 weeks to wait on repairs.

Replaced old battery with secured new battery.

I decided that the issue must be with the CMOS battery being dead and that replacement of the battery would solve the issue of data loss on power cycles. After removal and disassembly of the CTC I found the battery I had assumed was the issue.

Downloaded new Program and Corrected Registry values.

After installation of the repaired CTC unit, I reprogrammed the registry, cycled the power and no data loss accrued. Problem solved. At start up I still had an error screen for the e-stop. I later found that the PLC program also resides on the same non-flash memory as the Registry. I then verified the correct PLC program and downloaded it to the plc controller. Cycled power and found no software errors.

After pushing the pin(1) out of the Molex(2) connector I found the wire(3) was not clamped to the pin(1) at all. I made the obvious repair here which fixed the servo error issue for good.

After reviewing the machines schematics, I found that the probable cause was between the CTC and Servo Amp. After further investigation I found the signal wire from the CTC was in the interface jack but was not making good contact inside the Molex plug.

Saw was experiencing random episodes of errors in regards to the servo resulting in machine down scenario.

Bad wiring causing intermittent servo errors.

After reviewing the standard registry values, I found one value to contain the incorrect value of .100” that turned out to be the culprit. After updating this value the issue immediately disappeared.

“The saw has had issues for years where it would cut the first pc in every cycle after the 1st cycle .100” short. We had them work on it but they couldn’t ever figure it out” (Elvin Mills) Senior Maint. Supervisor. In the past maintenance would try tightening or loosening the drive belt tensioner in hopes to remove backlash or tweak things which would provide very little help. Operators would then fudge the parts nominal length when inputting to the saws length value. Between these two operations one could get the bad 1st parts and good parts to fall with-in side of the full +/- tolerance range. However it was extremely risky as these tolerances were borderline, more than not.

Issue that has long plagued the saw.

What was once thought to be a mechanical issue.