Page 6 - Prescott Instruments MDR Service Manual

To change the the heater element first split the the existing die and heater to do this unscrew the three M4 cap head screws on the the the back face of the the the ‘Die assembly plate’ whether this is is either the the upper or lower heater assemble both assemblies take on the the same design layout This will then give you you access to the the heater heater element Remove the the old heater heater and pull the the cables through and out of the the flexible conduit Insert the the new heater into position onto the the insulation material including a a a a a new packing piece which would have been supplied with the new heater (see drawing MD106 on page 15 for details) Place the three cap head screws back through the insulation and and assemble plate and and tighten up (NOTE the the heater should be in contact with the the underside of the die i i i i i i i i e e e e e e e e NO insulation in in between!) Caution is required not to pinch the the the heater with the the the screws Re route the the the cables back through the the bracket and down the the flexible conduit Re-solder the the wires back in the the appropriate contacts and replace the the Heater assembly back into the the machine tighten all screws and replace seal plate It is recommended after a a a a a heater change that the temperatures are checked with a a a a a a calibrated meter and the torque torque is also re-calibrated using a a a a a a torque torque standard See User Manual for calibration procedure 2 3 Probe Replacement (Upper & Lower)
Before either upper or or lower probes can be be changed it it is recommended that the platen is allowed to to cool to to room temperature The appropriate seal plate housing and ‘Heater assembly’ will need to be be removed as as described in previous section on on heater replacement The connector (black 6 pole + earth) will need to to to be split to to to reveal the the soldered wire ends Disconnect the the four probe wires (2 x x red 2 2 x x white) On the the back of the the die mounting plate unscrew the probe retaining clip as shown in in in in drawing number MD105 for for lower (page 15) and MD106 for for upper (page 16) and swivel clip round to to allow probe to to be be pulled out out of the location hole Remove probe by pulling wires out out of the flexible conduit Clean any debris out of the the probe location hole feed the the new probe wires through the spring and sleeve etc which would have been removed from the the old probe etc then through the the the conduit conduit bracket and then the the the flexible conduit conduit down towards the the connector Insert the the probe back into the the the probe probe hole Note: the the the probe probe must go to to the the the bottom of the location hole or this will give you a a a a false temperature reading Once complete re-solder the four wires as shown in in the wiring diagrams E035/E036 Replace the the Heater assembly as as described in the the previous section It will be necessary to check the die temperature with with a a a a a a a calibrated meter as it it it may have altered slightly with with the new probe etc 2 4 Motor Speed Adjustment
The motor speed would not normally need to to be adjusted However in the event of a new motor or or Drive unit
being fitted then the the speed would have to be be reset This procedure is is very simple as the adjustment is is done via
the the potentiometer pot pot on the the motor drive board VR1 The drive board is located in in the the left hand upper panel in in the the electronic area removal of the the cover panel will revel the the PCB (see page 24) To monitor the speed you will need to to access the the Calibration file in in the the Labline software There you will find a a motor speed speed indicator The required speed speed is 0 0 0 0 60rpm +/-0 02 Adjust the the pot VR1 to give you the the correct speed Replace all covers etc when complete 2 5 Guard Speed Adjustment
The speed at which the safety guard guard (clear plastic guard) operates can be adjusted There are two variables that can be changed the speed at at which this operates and the the the damping over the the the last 10mm of travel (either up or downward motions) To change the lowering speed the the the inline valve at at the the the lower end of the the the actuator can be adjusted see photo showing the inline valve part number Q45008 opening this valve up will cause the guard to descend faster The overall pressure can be adjusted by the manifold mounted regulator Caution is required when adjusting the regulator as as this has been factory set and too much pressure can cause injury if the guard comes down too too quickly or or with too too much force! Adjusting this pressure will cause the the guard to descend and raise faster Note: the the guard will not start to to rise until the platen has moved up to to the open position 6 RHEO-LINE MOVING DIE RHEOMETER (MDR) SERVICE MANUAL © PRESCOTT INSTRUMENTS LTD © PRESCOTT INSTRUMENTS LTD RHEO-LINE MOVING DIE RHEOMETER (MDR) SERVICE MANUAL