Peristaltic Pump

Hey guys,

So we are working on a 3D printer for our senior design project. We are Biomedical Engineers trying to build a printer for tissue engineering applications. We are wanting to print a UV curable polymer. While most printers heat a filament, we are hoping to pump the UV curable polymer with a peristaltic pump. However, we are stumped on how to translate filament feed rate to pump flow rate. Before we go ahead and purchase a pump, we wanted to have a better understanding of this relationship. Any clues?

Diameter of tube in pump = filament width
Nozzle size = nozzle size
Length of polymer drawn through pipe / pump steps (how ever you control your pump) = steps per mm

I maybe completely off track but surely is fairly simple?

... as the volumes aren't really big in the biomed-printing, why not a stepper-driven piston? ... it's pretty precise and can dispense high viscous pastes too ...

Some years ago I've assembled a medium sized dispenser with 6 UV-LED's, but the sizes can vary - look here: [www.reprap.org]

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Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

i must not be alone in thinking those pumps are named really poorly.

i would be willing to try treating the settings like that, i wonder though if you could deal with the pulsing that peristaltic are known to have.?

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[mike-mack.blogspot.com]

PLYUMP peristaltic extruder

Lot of data...

Quote
dissidence
i must not be alone in thinking those pumps are named really poorly.

i would be willing to try treating the settings like that, i wonder though if you could deal with the pulsing that peristaltic are known to have.?

We have two options to negate the pulsation. We are considering having two pumps with 180 degree offset, so while one is stalling the other has max flow, and the other option being use one pump with long, flexible tubing that will reduce the pulse wave. Preferably the later, for simplistic reasons, but the first is probably doable as well.

Edited 3 time(s). Last edit at 01/30/2014 07:55PM by hsteven7.

I have two more. First, a simple solenoid valve to release the built up pressure, kind of like the gun on an air compressor. You'd also need a regulator valve to ensure stable pressure and a tank to store that pressure. Second, use a smaller pump with high "steps per mm" or in this case "steps per CC" to offset the pulsation.

Edited 1 time(s). Last edit at 01/30/2014 09:08PM by ohioplastics.

I have changed jobs recently. I now sell pumps in the water and wastewater industry. Currently I handle centrifugal pumps, mechanical, hydraulic and solenoid diaphram pumps, lobe pumps, peristaltic pumps, progressive cavity pumps, and more.

One company I rep Netzsch has a progressive cavity pump with a servo motor drive that is used to dispense the foamed in place gaskets you see on electrical cabinets. It also is used for glues. That is pretty close to what you want, virtually no pulsation and can do high pressures. Another possible choice with low pulsation is a gear pump. They make some really tiny ones these days.

i think these guys use small gear pumps, https://www.youtube.com/user/LilGiantsConstrCo/videos, they always amaze me. i have always wondered if reprap could ever learn any tricks from these guys.

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[mike-mack.blogspot.com]

@hsteven7 :

Moineau stepper extruder
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Quote
hsteven7
we are stumped on how to translate filament feed rate to pump flow rate

I assume you will be using a stepper motor to drive whatever pump system you end up with (and if I was doing what you're doing I would go with Richrap's Universal Paste Extruder for 3D printers (see above post from A2)).

If you're using a stepper motor, then the only setting you would really need to mess with would be the steps per unit for the extruder (see here for example: [wiki.ultimaker.com]). The M92 code lets you set this temporarily.

Here is a link to the Netzsch pumps I wrote about earlier

[www.metermixtech.com]

i wonder if a crescent gear pump could not work with a reprap for thicker liquids.

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[mike-mack.blogspot.com]