Resin Mixing Pump

I have noticed that FTD Snow White, a heavily pigmented resin, tend to separate over a long print.  Someone on the D7 Facebook Group had used a dosing pump to keep resin mixed so I decided to do the same.

Here is the pump that I used (from Amazon UK).  The tubing that I used was from eBay and was described black silicon tubing with an inner size of 2mm and an outer of 4mm.

The pump vibrates when it operates so it should probably be turned off when the printer is curing a layer.  This means putting it on the 2nd fan output on the power supply so you can control it with "M106 P1 S255" for on and "M106 P1 S0" for off.  I guess the alternative would be to have it off the printer and running constantly?

The mount that I designed for the pump is pretty simple and is available on Thingiverse for download.  Ideally I would have liked the hoses to feed around the back of the vat but there just was not enough clearance for the build plate to travel.  As you look at the picture of the printer the left is suction and the right is output.  I route the suction tube to the near right corner and the output to the far left corner.   The tip of the input tube is cut at an angle so it does not attach itself to the FEP.

Controlling the pump entails putting the following gCode into the printer setup:

Below is a ten hour print.  There is no sign of pigment leaching which I would have  expected towards the end of the ten hours.