Blog Stratasys 3D Printer - Weight Test
Ever wonder why your Objet30 print quality has been diminishing lately? There are many different complications that can contribute to the poor part quality, one of the most common being the heads voltages. The weight test is an important calibration. The purpose of a weight test is to provide the correct amount of voltage to each print head so the printer can jet the appropriate amount of material onto the bed. How can you tell that your machine's heads need to be calibrated? Parts will look like they are "sinking" or "melting". If the Objet30 is not printing the correct weight, the layer thickness is lower than what the machine is expecting. The heads over time get further and further away from the part. This causes the heads to jet further away from the part as the part gets taller. Also, the UV lamp distance increases from the part as the part gets taller. This will cause the resin to not cure properly. To fix this issue, perform a weight test calibration. It is simple to run a weight test.
(Note for clear material on the Objet30 pro, you need to run the regular weight test and the weight test special. Insert the data for the calculations into the "Special" section of the spreadsheet if running weight test special.)
First, you need to put the machine into maintenance mode. To do this, on the embedded computer, move the mouse cursor into the bottom right-hand side of the screen. With the cursor in the bottom right, press CTL + ALT + M. You should notice another drop down menu appear on the top of the screen.
Once in maintenance mode, click on "Maintenance" > "Calibration".
You will notice a window pop up. Make note of the "Current Voltage" fields for both model and support. Next, click on "Maintenance > "Modes" > "Weight Test" ("Weight Test Special" for Objet30 pro). You Objet30 is now ready to print the weight test. As soon as the printer is put online, (big red button that starts the print) the printer will start the weight test. Once the job is finished there will be two patches on the bed. One model patch and one support patch.
Look for missing nozzles on the patches. Missing nozzles look like a line missing in the patch. You are allowed 15 nozzles missing total on each patch, or 5 nozzles missing in a row. If you have too many missing nozzles, you may need to replace the print head.
Carefully remove the model patch and weigh it on a gram scale. Make note of the weight in grams. Leave the model patch on the scale and tare the scale. Carefully remove the support patch and weigh it on the scale using the model patch as a platform. Make sure you get all of the support material onto the scale. This tends to make things neat. Make note of the weight in grams of the support material.
Once all the information that we need is acquired, you can proceed to make the calculations necessary to calibrate the heads using the excel spreadsheet or android app.
Excel Sheet:
(Note for clear material on the Objet30 pro, you need to run the weight test special. Insert the calculations into the "Special" section of the spreadsheet. You will need to run BOTH calibrations on the Objet30 Pro)
Android App:
Once the calculations have been made, you can adjust the head voltage. In the maintenance menu, select "Calibrations". In the window, under requested voltage, input the result from the previous calculations in both the support and model columns. Click Calibrate. After the current voltage stops moving, click save. Run the weight test again to see if the weights are in specification. If they are, that's all that's needed. If not, run the data through the calculation again.
Note that the maximum voltage for the model head is 44v and the maximum voltage for the support head is 37v. If you are at the voltage limit and still getting low weights, you may need to replace your print head.
Daniel Lindsay | Field Service Engineer