The rebirth of the peristalic pump?

I think a lot of us think spackling compound (US) polyfilla (UK and maybe everywhere else) is a good bet. If you are using no temp fast drying resins then maybe wax would be ok. I thought of wax early on but knew it would not work well with the hotter temps of some of the plastics we use. I believe Adrian noted that even something fairly liquid would however support something just laid lightly across it. I hope you find some good fast curing cheap materials whatever they are Good luck. And if you didn't catch it yet, check out the thread and the link about the hackable extruder. Bottom line, aquarium pump and some tubing leading to container. I don't know what kind of pressure that would give but someone will be telling us what its good for soon I bet.

Hello guys! I am new on the forum but I am following your progress from some time.

I would like to show you my progress with a new kind of peristaltic pump paste extruder. You can see it in action here: paste extruder

The extruder is a screw driven peristaltic pump. The screw shaft pinches the elastic tube which is aranged paralell with the screw axis. Two chanels are in anti-phase to minimise pulsation (in fact pulsation almost cannot be seen).

In the video I used some hair gel for the first test. I choosed it because it has very good flow, Nozzle dia is 1 mm, and layers 0,25mm.

There are still a lot of improvements to be done as this is my first prototype.

Regards,
Ioan

Eight hours later, the video is "still uploading"

A screw driven design sounds very promising, as you get a get a constant flow, right?

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Generation 7 Electronics	Teacup Firmware	RepRap DIY

Hi Traumflug!

Sorry, I saw this morning that the video is not available yet on vimeo so you can watch it here: peristaltic paste extruder

Yes the flow is constant and of course can be modified since the pump is stepper motor driven. However air bubles ar the big enemy. If the paste contains air bubles they will affect the deposited layer.

The pitch of the screw shaft is 12 mm so the effect is the same as in a multiroller standard peristaltic pump. I will post later more pictures and an other video.
regards,

Ioan

Here are some photos of the printing head: paste extruder

It still have some bugs which I need to fix. Hopefully next week I will post the stl files so anybody can try this design and improve further.

Note that the print head is adapted for a rapman 3d printer but I am sure it is easy to attach on a mendel printer.

Total parts cost don't exceed 10 euros except the stepper motor of course which is a NEMA17.

regards,

Ioan

Great work.

I don't quite understand the plumbing from the pictures. You have two anti-phase pumps that presumable meet at a Y - junction before the nozzle? One seems to be fed from a syringe. Is that just a reservoir? Is the pump able to suck the plunger down the syringe? Where does the other pipe go to ?

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[www.hydraraptor.blogspot.com]

Yes, great work indeed.

What's me bothering a bit is that screw apparently sliding sideways over the elastic tube. Without some sort of rolling mechanism, I'd expect this to grind the tube away within a few hours.

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Generation 7 Electronics	Teacup Firmware	RepRap DIY

Hi guys!
Here is a second video printing viscous glazing cream: printing glazing cream

@nophead - yes the syringe is only a reservoir. from syringe there is an T connector at the inlet and the two pvc tubes goes along both sides of the screw shaft. The pumping elements (cream colour) are cheap latex tubes from perfusion sets (0.25 euro/pcs). At outlet there is an Y connector (not pictured) right before the nozzle.
And yes the pump can suck the syringe plunger down including the fluid inside. I didn't measured yet how much negative pressure can get. Anyhow, by looking at my second video I think you will understand exactly how the pump works.

@traumflug - yes, this is the main disadvantage of this design! It has many many advantages over classic rotor peristaltic pumps but this is an drawback. Perhaps this is the reason they never been used on an larger scale.
But there is a trick! I am using an ptfe foil between the screw rotor and the elastic tubes arranged in that manner that the tubes will not wear out (they are only pinched). It is running so smoothly that is making the NEMA 17 motor largely oversized for that job (it is a 0.47 Nm holding torque). Also it works like charm using ordinary Scotch tape instead of ptfe foil.

Anyhow the tubing and pumping parts are so cheap I always drop them in the trash istead of washing them...

Regards,

Ioan

P.S. @nophead - sorry I now understand why you asked me where is going the second tube. In that picture I was using two syringes to see if the pumping channels are delivering the same amount of fluid.

P.S. 2 I updated my photo album with a heart shaped glazing. Since I am an skeinforge dummy it needs a lot of fine tuning....

Edited 3 time(s). Last edit at 02/27/2011 02:13PM by Ioan.

Hello guys!

I have uploaded the peristaltic paste extruder on Thingiverse: paste extruder

Enjoy!

regards,

Ioan

Hello people!

Here is my third video of the paste extruder: high speed printing

Printing polymer blend at 16mm/sec., 0.5 mm nozzle, 250 micron layer.

regards

Ioan

Hi Loan. Great work!

You might be interested in Kraftmark's "fabEpoxy" material for your extruder. They've engineered an epoxy blend with low shrinkage and very long "pot life" specifically for 3d printing. If you can pump it, you should be able to make very high strength parts. I'd be interested to see how it works!
http://www.kraftmark.biz/kraft.fabepoxy.html

Thanks for the tip! I will try out asap.

regards,

ioan

I am absolutely in love with this implementation. I have been toying with a peristalic pump-driven color system, but this sounds like a good stepping stone in experience.

Have you tried running it multi-head? I would like to try to get this and plastic on the same machine.. and to possibly blow hot air through the hot-end nozzle to 'bake' a clay or metal/clay mix.

What is the smallest feasible motor?

Another thought.. if you had both heads and heat, you could extrude a rubber-like seal between two pieces of plastic?

Hi Jason,
Sorry answering you so late. Life forced me to put all the work on the pump on a halt. So the project is frozen from many months so I cannot answer your questions. Hopefully after the New Year I can restart the work.

Did you built the pump? Do you have some findings?

regards,

Ioan