The following article will take you through the how and why you should calibrate your load cells on a Stratasys PolyJet Desktop 3D Printer. The load cells measure the weight of the material bottles in grams to determine which bottles to use first and when to stop using them. To keep them as accurate as possible, we recommend doing this calibration once a month for heavy users (125+ hours a month) and no less than once every other month for all other users.
This calibration can be found by accessing the Options Drop Down. In the Options Drop Down, under wizards, you will see "Load Cell Calibration." We recommend doing all 5 cells each time (2 support, 2 model, 1 waste).
When you open the wizard it will ask you to pick which you would like to calibrate- pick all 3.
From here, it will ask you to remove just one of the bottles, but it is much easier and faster if you remove all 4 bottles and the waste box at this point. After you have removed them close the material drawer so that they will be as stable as possible when calibrating.
Once you have checked off that the first bottle is removed and you clicked next, you will see a display with a current level number in a box under the label A/D.
The exact number you see in the box is not all that important to calibrating the cells. However, the amount of movement it has is important. When you first see the number pop up, 2176 in this case, we do not want to have it vary more than +/- 10 values from this. So the cell shouldn’t read less than 2166 or more than 2186 while watching it. You will only need to watch it for a few seconds. As long as it hasn’t gone over those numbers it is considered stable. If at any point the cell does happen to jump around past those numbers, cancel out of the wizard, close the embedded software, restart the software, and try the calibration again.
You will need to check this number for all 5 of the cells – check the box saying the weight is stable and then hit the next button to advance to the next cell. It will ask you to remove the bottle from that cell. You can just hit the check box and advance to the actual calibration area with that cells current level. Remember each cell will most likely read a different number than the previous cell. That is OK.
Once you have completed calibrating all 5 cells you will need to hit the done button to close the wizard. Then, you will need to reinstall all 4 bottles and the waste container in the drawer.
1) Do not tighten the waste container cap too much because it can cause the bag to twist. This will cause the waste container to overflow. It only needs to be slightly snug. Make sure it does not hang up or hit anything when opening or closing the drawer.
2) Insert the bottles as close to the same position as they were before. This will prevent leaking from multiple puncture holes or being inserted on an angle.
For a video tutorial of this procedure please visit our YouTube page.
Stratasys Field Service Engineer
Computer Aided Technology, Inc.