Troubleshooting - Danville PrepStart Manual Del Operador

3.3 TROUBLESHOOTING

Problem
Plugged nozzle
Slow cutting performance
Abrasive flow does not shut off immediately
Excessive powder flow
Internal air leak
Weak powder flow
3.4 PINCH TUBE RENEWAL
The pinch tubes can be easily renewed in the office provided it has not ruptured.
1. Depressurize and disconnect from air.
2. Remove the abrasive jar cap, the abrasive, and the upper o-ring on the jar.
3. Remove the four Philips head screws in the underside of the PrepStart (see Fig. 4.3).
4. Lift the top cover off, tilting the rear of the cover up first.
5. The pinch valve is an aluminum cylinder near the outlet port (see Fig. 4.4). Two black
plastic tubes passing through (see Fig. 4.3) the cylinder are the pinch tubes. The pinch spot
is renewed by pulling both tubes with pliers, about 7mm toward the rear of unit.
6. Reassemble in reverse of above procedure.
Troubleshooting
Blow air backwards into the disconnected nozzle.
Slow cutting is caused by: weak abrasive flow, or low pressure and/or a nozzle that is small size, or worn out. A microscope slide is included for a standardized cut test.
Test: With a .019 tip held perpendicular at 1mm, with maximum abrasive flow and 100 psi, the slide should be pierced in 3 to 5 sec.
1. Check the abrasive fill and for the correct brass tuning cap inside jar.
2. Check the pressure setting: higher pressure dramatically increases the cut speed.
3. When the PrepStart is activated the pressure gauge should not drop more than a few psi (1/10 bar). See 'Air Source' (Sect. 1.2).
4. Check nozzle size; (.015" nozzles will cut slow).
5. Set powder control to maximum (clockwise).
6. Check for weak powder flow (see weak powder flow below).
1. Empty waste powder chamber.
2. Pinch valve or waste powder chamber filters may need service.
1. Ensure the abrasive tuning cap matches the size of abrasive used (27 or 50 micron).
2. Empty the waste powder chamber.
3. Ensure abrasive level in powder jar is below tuning cap.
Check for excessive pressure. Pressures above 125 psi (8.3 bars) will be automatically vented by an internal safety valve.
Weak abrasive flow will greatly reduce the cutting efficiency. The PrepStart is tuned to use about 5gm/min. at 100 psi (6.7 bars) at the maximum powder setting.
The abrasive stream is most easily viewed when sprayed across a dark background with good lighting. The spray should appear light but clearly defined. Weak
abrasive flow can be caused by:
1. Low powder in the abrasive jar.
2. Incorrect abrasive tuning cap.
3. Low abrasive setting or moist abrasive.
4. Plugged jar metering holes result from moisture contamination, and prevents abrasive from being picked up (see: Recommended Abrasives pg. 1).
(Dump out moist abrasive. Inspect the bottom of the jar for abrasive collecting around the inner column. A ring of more than 4mm of abrasive will block
the metering holes. Remove the abrasive with an explorer.)
Solution
After several 'renewals' the pinch tubing will have to be replaced at a service center. Please
note that pinch valve service should be performed at an authorized service center as opening
the cabinet will void the warranty.
3.5 RETURNS & SHIPMENTS
Prior to the return of a system, or any portion thereof, you should contact your dealer for
servicing. Your full service dealer is equipped to handle most repairs of the PrepStart. Should
your unit require a return to the factory, your dealer will arrange this for you. Shipment of a
unit to the factory without the proper return authorization may result in a returned shipment.
If you have any questions about these procedures, please contact Danville at 1-800-827-7940
or fax to 1-760-743-7975.
3