Specific Process Knowledge/Back-end processing/Polymer Injection Molder/Eject: Difference between revisions

Revision as of 12:49, 8 February 2018

Ejection

Once the mold has opened, the sample must be ejected from the mold to enable the robot to pick up the sample. This is done by pushing out ejector pins from the mold, which in turn will push out the sample. When samples are picked up reliably by the robot it is usually not necessary to adjust these settings. The settings for the ejector demolding settings are can be found on the 'Mold open' screen:

Ejector pin parameters are found on the 'Ejector' screen.

Advance profile: These settings control how the ejector pins advance. The advance speed (green curve) and advance force (red curve) can be edited using the '=' or arrow buttons or by editing individual points on the graph. Generally it is not advisable to increase the advance speed above a few mm/s. And importantly: Under no circumstances should the advance force be increased above 8 kN! Otherwise the ejector pins may be damaged (bend or even break)! It is recommended to keep the advance force at 6 kN or below and only increase it to 8 kN if samples cannot be demolded reliably.

Retract profile: These parameters control the ejector pin retraction and is edited in the same way as described for the advance force.

Ejector stroke position: These settings control the positions of the ejector pins in the retracted and advanced position. It is recommended to leave the 'Ejector retracted position' around 25,6 mm. The 'Ejector pin advanced position' can be fine tuned if you have problems with unreliable robot pickup, but 56,0 mm usually works well. If you make changes to the 'Ejector advanced position' make sure to adjust the robot take-off position as well. Otherwise you risk missing the sample or that the sample is pushed hard into the robot arm and thus risk damaging both the robot and your samples.

Scrolling down will reveal a few more important settings regarding part removal:

@@ Line 5: / Line 5: @@
 [[File:07a-eject.png|600px|thumb|left|Ejector pin parameters are found on the 'Ejector' screen.]]
 <br><br>
-*'''Advance profile''': A constant speed can be set using the '=' button or the arrows. Alternatively individual points of the graph can be edited. If samples tend to break during demolding it might help lowering the opening speed. In general the speed should be low towards the end position (fully open position) to avoid violently slamming the mold against the end stop.
+*'''Advance profile''': These settings control how the ejector pins advance. The advance speed (green curve) and advance force (red curve) can be edited using the '=' or arrow buttons or by editing individual points on the graph. Generally it is not advisable to increase the advance speed above a few mm/s. And importantly: '''Under no circumstances should the advance force be increased above 8 kN!''' Otherwise the ejector pins may be damaged (bend or even break)! It is recommended to keep the advance force at 6 kN or below and only increase it to 8 kN if samples cannot be demolded reliably.
 <br>
-*'''Retract profile''': This value defines how far the mold opens. It should generally be avoided to open the mold all the way to the end position, since this causes the mold to bang violently into the end stop. If this happens (you hear a bang every time the mold reaches the open position) decrease the mold stroke position by a few millimeter (e.g. change the stroke from 235 mm to 232 mm). Remember that changing the opening stroke will also change to robot's take-off position, so remember to adjust the take off position accordingly.
+*'''Retract profile''': These parameters control the ejector pin retraction and is edited in the same way as described for the advance force.
 <br>
-*'''Ejector stroke position''': These settings change how the robot is allowed to move around the mold. These settings should generally not be changed (be very careful if you do) to avoid crashing the robot into the mold.
+*'''Ejector stroke position''': These settings control the positions of the ejector pins in the retracted and advanced position. It is recommended to leave the 'Ejector retracted position' around 25,6 mm. The 'Ejector pin advanced position' can be fine tuned if you have problems with unreliable robot pickup, but 56,0 mm usually works well. If you make changes to the 'Ejector advanced position' make sure to adjust the robot take-off position as well. Otherwise you risk missing the sample or that the sample is pushed hard into the robot arm and thus risk damaging both the robot and your samples.
-<br><br><br><br><br><br>
+<br><br><br><br><br><br><br><br>
 Scrolling down will reveal a few more important settings regarding part removal:
 <br>
 [[File:07b-eject.png|600px|thumb|left|Scrolling down on the 'Ejector' screens reveals part removal settings.]]
 <br>