Shrink Compensation

Shrink Compensation for ProJet^® VisiJet^® Materials

Material shrinkage occurs in thermosets as they transition from liquid state to solid state during the curing process.

The 3D SPRINT™ Client Software has features that allow the user to compensate for the natural shrinkage of the material in order to fine tune the accuracy of a part.

These shrink compensation values serve as general guidelines to setting shrink compensation. Part building and cleaning in a controlled process will best determine the optimal shrink compensation values for a particular geometry.

ProJet® MJP 2500W / IC Default Shrink Compensation Values for all materials (as of 20180607) are as follows. New default values MAY be rolled out without software update notification.

Identify the exact X and Y dimensions of the part using a CAD program.

• Most CAD programs and simple .stl file viewers will provide a way to view a part with its dimensions.
• Make note of the actual X and Y dimensions as XCAD and YCAD.

Build and clean the part and take measurements of the finished part.

• It is recommended to measure along the critical dimensions of the geometry, take measurements in multiple areas and take an average of the values.
• Measurements can be made using calipers or more advanced metrology methods.
• Make note of the X and Y dimensions of the printed part and mark them as XPART and YPART.

NOTE: If the measurement of the finished part is different from the measurement of the CAD model, fine tune the accuracy using scaling factors.

Determine the Scaling Factor to use for the next build

Use the following formula to calculate the scaling percentage to be used for fine tuning the build:

XCAD = XCAD x (1 + X Scaling Factor) x (XPART / (divided by) XCAD)

YCAD = YCAD x (1 + Y Scaling Factor) x (YPART / YCAD)

Therefore,

X Scaling Factor = (XCAD - XPART) / XPART x 100 (answer will be a percentage)

Y Scaling Factor = (YCAD - YPART) / YPART x 100 (answer will be a percentage)

Example:

X measurement of CAD model = 3.000"

Y measurement of CAD model = 5.000"

X measurement of printed part = 2.998"

Y measurement of printed part = 4.989"

X Scaling Factor = (3.000 - 2.998) / 2.998 x 100 = 0.067%

Y Scaling Factor = (5.00 - 4.989) / 4.989 x 100 = 0.22%

Applying Shrink Compensation Values

There are two ways (Methods A and B) to select or enter new custom Shrink Compensation for the job. 

Method A

Enter standard Shrink Compensation Values for the material or entire print job.

1. Open 3D SPRINT™ Client Software and select Print > Printer Tools > Printer Setting.

2. Select the Add Button.

3. Give this new Shrink Compensation a name and click SET.
4.  Enter the new XYZ values, click SET.

5. Now the printer is defaulted to the new set of shrink compensation values. The bottom right corner information window is providing the new maximum printable size for XYZ accordingly per shrink compensation. You can now load jobs and print to the printer using these Shrink Compensation values.

Method B

Select Shrink Compensation Values for this material.

1. Open 3D SPRINT™ client software and select the Print > Printer.
2. Select the printer (use cursor to show printer  information) you wish to print the job with and then click Next.

3. Select material for the job, click Next.

4. Select Print Mode, and then click Next.

5. Pick your Build Style with Shrink Compensation values entered in Method A and click Set.

6. Now the printer is set to print with the selected shrink compensation values. The information window is showing maximum printable size for XYZ accordingly per Shrink Compensation. You can now load jobs and print to this printer with these particular set of Shrink Compensation values.
7. Now this job is ready to print with the chosen shrink compensation values for the parts. You can now add the job to the Print Queue for printing.

Print your part(s) with scaling factors and confirm by measuring. Process may need to be repeated depending on the various geometries of parts.