Snipe Problems on a Through Feed Moulder 2: Top Snipes

Checklist table of problems and solutions for moulder operators. December 1, 2006

Reprinted with permission from Diehl Machines, www.diehlmachines.com.

Troubleshooting Snipes on a Through Feed Moulder -
Top Snipes
Description
Probable Cause
How to Correct


A snipe on the top of a finished part created by the top spindle and on the leading end of the part.

Too little chipbreaker pressure.

Increase the chipbreaker pressure.

Chipbreaker too far away from the cutterhead.

Slide the chipbreaker toe towards the cutterhead. Be certain the toe does not hit the knife.

Sliver lifting stock.

Clean out the machine.

A snipe on the top of a finished part created by the top spindle and on the trailing end of the part.

Not enough holddown pressure.

Increase the holddown pressure or lock the holddown in place.

Holddown too far away from the cutterhead.

Slide the holddown towards the cutterhead. Be certain the cutterhead knives do not contact the holddown shoe.

Excessive stock removal with top head.

Increase the depth of cut with the first bottom cutterhead and/or the first top cutterhead.

Lower infeed roll too high.

Set the lower infeed roll 1/32" above the infeed table.

Chipbreaker too low.

Set the yield of the chipbreaker at 1/8" to the thinnest stock.

Bottom cutterhead is set lower than the outfeed table.

Check the setting of the cutterhead with the outfeed table with a straightedge.

A snipe on the top of a finished part created by the top spindle and on either or both ends of the part.

The holddown is not parallel with the bed plates.

Use a dial indicator to adjust the holddown shoe.

Stock may be bowed.

Run the stock into the moulder with the bowed face down.

Unsupported pattern on the outfeed table. The pattern rotates to one or both sides.

Place a support on the outfeed table to prevent the part from moving.

Pattern is unsupported by the holddown. The pattern rotates to one or both sides.

Create a special holddown for the part that holds the part down on both sides. Can be a counter-profile holddown.

Long stock is unsupported after leaving the moulder.

Place a table or conveyor under the stock to support it while it is leaving the machine.

Deep snipe from the first bottom cutterhead.

Check the setting of the first bottom cutterhead.

Thin stock.

When running thin stock it is necessary to set the chipbreaker and holddown shoes as close to the cutterhead as possible without hitting the knives. Thin stock finishes better if the ends are kept butted up.

Intermittent feedroll too high or too much pressure (only on machines with two top spindles).

Reduce roll pressure. Set the lower roll at 1/32" above the bed plate.

See other articles in this series at:
Bottom Snipes
Left Side Snipes
Right Side Snipes

Reprinted with permission from Diehl Machines, www.diehlmachines.com.