Hyd-Mech S-23A - Consistent Inaccuracy; Linear Inaccuracy

Pg 43 S22A / S23A mits 2001
CONSISTENT INACCURACY
(make sure blade kerf value is correct)
- change "Actual Pos." parameter to 1. This will make the PLC show actual shuttle travel in AUTO
With no material in the machine:
- program JOB 1 for 2 pieces of 5" length, JOB 2 for 2 pieces of 10" length, and JOB 3 for 2 pieces of a
length as one shuttle will allow.
- enter JOBS 1, 2 and 3 into QUEUE.
- record measurement on the display each time the shuttle vise reaches the target length and closes. It
should equal the required length plus the programmed kerf value. Check that this measurement is +/-.002" for
each length. If the overshoot /undershoot is very inconsistent, it could be related to an incorrect shuttle cushion
period. This may be caused by "Decel. Dist." parameter being set too low, defective fast or reverse output
relays on the PLC, or the hydraulic cushion valve (located at the hydraulic manifold) may be faulty.
LINEAR INACCURACY
(not valid for machines with linear encoder)
i) - load machine with a piece of stock for test cutting
- open parameters screen
- initiate length calibration (see 48)
- re-enter new ACT LTH (Actual Length) value
- recut test lengths and check if accuracy is satisfactory.
NOTE; Linear inaccuracy may be corrected in two ways, by using the length calibration as described above or
by adjusting the LTH CONST as follows;
-load machine with a piece of stock for test cutting
- program the PLC to cut two pieces each of 1", 12" and a length equal to a shuttle and a half of the machine
being checked.
-make the cuts and measure as a accurately as possible (vernier caliper)
-using the formula provided below, calculate the new parameter “LTH CONST”
Formula for determining new parameter “LTH CONST”
Measured length divided by Programmed length X Existing constant = New “LTH CONST”
i.e. Programmed length = 1.00" Measured length = .999" -0.001" short
= 12.00" = 11.988" -0.012" short
= 60.00" = 59.940" -0.060" short
Existing parameter “LTH CONST”=0.001256
11.988 divided by 12.00 x 0.001256 = 0.001255
The new parameter “LTH CONST” would be 0.001255. This value should be entered as the new “LTH CONST”
parameter and test cuts repeated. Adjust the parameter again if necessary.
GENERAL RULE: Lowering the parameter value = longer shuttle travel = longer parts
Increasing the value = shorter shuttle travel = shorter parts
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