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 5600 Default Shrink Compensation Values for all materials (as of 20171101) are as follows. New default values MAY be rolled out without software update notification.

Material X Value Y Value Z Value

VisiJet® CR-CL, Rigid Clear Build Material (v1)

0.2% 0.4% -1.1%
VisiJet® CR-CL, Rigid Clear Build Material (v2) 0.1% 0.1% -0.5%

VisiJet® CR-BK, Rigid Black Build Material

0.1% 0.4% -1.1%

VisiJet® CR-WT, Rigid White ABS-like Build Material (v2)

0.1% 0.1% -0.5%

VisiJet® CE-NT, Elastomeric Natural Build Material

0.2%

0.1% -0.1%

VisiJet® CE-BK, Elastomeric Black Build Material

0.2% 0.1% -0.1%

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%