Markforged 3D Printer Makes Part for Pump

Markforged 3D printer to the rescue – The story of fixing a spa pool

CADPRO Systems has a Markforged Mark Two 3D printer and an Industrial X7 that we make commercial parts on and do a few homers!

The story

In August 2013, I purchased a new spa pool that was about half the comparable price of a well-known brand. That should be a great big warning as to what I was going to have to put up with as soon as the warranty expired.

  • The recirculating pump failed to run – turned out that the output relay failed so I chose a spare one.
  • The same failure again but this time it blew a hole through the PCB.
  • Repaired that with copper wire and that ran for a while.
  • PCB failed again so completely replaced all the electrical and electronics with a good brand. Been good ever since.
  • The first recirculating pump seals failed so I replaced them and it was good for another 6 months.
  • Replaced the pump with the same model pump. The mounting holes were different but the height was OK. Good for 2 years.
  • Bought a different brand pump as a replacement thinking it would be different. Turn out that only the motor is different with different mounting holes.

This is when I thought I have access to a Markforged 3D Printer so I’ll make a replacement mounting plate for it.

Designing new mounting plate

The mounting points on the failed pump are part of the motor casting. The pump impeller cut a hole through the scroll and separated into 2 pieces. The seal also failed.

Spa Old Pump Elevation

Inside Pump  Spa New Pump Elevation

 

 

 

 

The new pump had a removable black plastic base plate that was too high with the mounting holes in a different location.

With a little measuring, I modeled it in Fusion 360. Why not Inventor? – I was a bit rusty with Fusion 360 and wanted the practice.

Spa Pump Mounting Bracket

Fusion 360 Pump

The Markforged Mark Two was setup with Onyx and Carbon Fibre which would have been ideal.

The part was just too big for the Mark Two so I opted for the Industrial X7 with a bigger bed. It was setup with tough Nylon and Kevlar.

  • Tough Nylon would have been too flexible so some continuous fibre was required.
  • The Kevlar would have done but we had some Fibreglass that I wanted to try.

In Eiger, I made all the appropriate settings and added fibre in 4 layers – bottom, middle of the bottom part, through the highest stress area on the vee area and again at the top.

In the image below, you can see the concentric fibres around the perimeter and isotopic on the others. The isotropic layers alternate angles for more even strength properties.

Eiger Pump

3D Printing

The 3D print started out looking 100% but then the support structure started to lift off the bed. What to do? I let it run and was impressed with the final outcome.

What I should have done is ‘Use Brim’ in Eiger so that the support structure has a decent surface to stick to. I think the small heat build-up during the print caused enough load to peal the frail supports from the bed.

20180623_094003

 

 

 

 

 

Fitting

To my tremendous satisfaction, the 3D printed part fitted perfectly.

Plate in place

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The cold water filling the spa is only 11℃ so it will be a few hours to get it up to 38℃.

 

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