The last heat sealing trial completed at our factory produced seals, however the quality of the seal was marginal.  Although the Quad sealed all four sides, we still experienced cut marks.  Cut marks are dimples that are caused by wrinkling of the impulse wire.  And wrinkling happens when the rocker pressure is too low.  On the last trial, we had the rocker pressure at 75 psi.  Once dimples occur, it is virtually impossible to flatten the wrinkled impulse wire.  And, as a result the impulse wire will always have a tendency to wrinkle in the same area. 

Having top and bottom wrinkle at the same location is statistically a long shot.  So the wrinkles you see are most probably caused by one side (top or bottom), not both, unless the top contributes some and the bottom contributes others.  If we could have kept the machine longer, we would have isolated which (top or bottom bar) is contributing to the dimples, and tried smoothing out the severity of the dimple by placing patches of TCF over the dimpled impulse wire.

In the interest of time to get the Quad operational, I suggest we replace each impulse wire with new wire.  Save the removed wire by carefully rolling it onto a stable core.  Depending on the condition of the removed wire, it may become a resource for C & D.  Since you only have about 75 feet of impulse wire (more is on order), I would suggest you replace the wire on the sealer creating the most dimples.  However since the wrinkling presumably was caused by the 4X Cylinders, please first install the 17X Cylinders to assure that wrinkling will not occur again on the replacement impulse wire.

Before replacing the impulse wires, I would suggest you test the seals made with the existing impulse wire.  Replacing the impulse wires should be your last step after everything has proven to work correctly, ie. each heat sealer makes seals. 

Prior to shipping the machine, the last sealing trial settings were as shown in the following table.  Keep in mind that the numbers shown are in tenths such that 50 tenths is really 5 seconds; however to set a time of 5 seconds, the PLC requires that you input 50.

9X on A/B A B C D Sealing Time 63 50 25 26 Cooling Time 50 50 38 42 Sealing (PSI) 50 40 50 50 Rocker (PSI) 75 75 100 100

Again, please remember that the parameter values shown above are for use with 4X Rocker Cylinders on C & D; and 9X Rocker Cylinders on A & B.

So, before testing the machine configured with 17X Rocker Cylinders on A & B, and 4X Rocker Cylinders on C & D; please configure parameters as follows:

Heat Sealing Parameters.  Parameters controlling heat sealing include:  Sealing Time, Cooling Time, Sealing Pressure, and Low Pressure Heat Sealing Time. 

Sealing Time is the time (seconds) that the impulse wire is energized.  Cooling Time is the time (seconds) that the impulse wire is off.  Sealing Pressure is the pressure (psi) on the top heat sealing bar.  Low Pressure Heat Sealing Time is the time (whole seconds, not tenths) that the heat sealing pressure is off and when the impulse wire is energized.  Low Pressure Heat Sealing time is a subset of Sealing Time.  This means, that if Sealing Time is set for 60 (6 seconds), and Low Pressure Heat Sealing Time is set for 2 seconds, that the total sealing time on the first (only) pulse is 6 seconds minus 2 seconds, or 4 seconds under pressure.  Subsequent pulses are not affected by Low Pressure Heat Sealing Time.  The purpose of the Low Pressure Heat Sealing Time was to allow the rockers to apply pressure on the initially heated impulse wire.  However, the longer the sealing time, the less effective the Low Pressure Heat Sealing Time.

Cooling Time is somewhat misleading.  Absence of energized heat does not mean that the material doesn’t ‘feel’ heat.  It does.  It is just that during Cooling Time, the heat does not continue to increase.  During Sealing Time, the heat continues to increase ... time is the only control.  This model does not include any other temperature control.  We’ve found that Cooling Time holds the temperature in a similar way that a PID controller would hold a set point.  Of course there are limits.

The delay time before the sealing bar is pressured is found on the Internal Specification page on the PLC. Factory default setting is 2 seconds.

After you set the parameters as shown on the second table (for 17X), make some seals.  Based on the results, make the following basic changes.

A.  If the cut marks seem to have increased on existing impulse wire, increase rocker pressure by 5-10 psi; however maximum rocker pressure can not exceed 70 psi.

B.  If you get more cut marks or only cut marks, but no seal, then increase sealing pressure by 5 psi (make sure that rocker pressure is equal to or greater than sealing pressure); and consider decreasing Sealing Time by 0.1 second; and/or increasing Cool Time.

Once you begin to get good seals with or without an increase in cut marks, replace the impulse wire with new wire and restart trial testing.  Additionally, email all current parameters to Glenn.