After getting access to a Lulzbot 3D printer, [Tim] designed a 3D printable peristaltic pump. The design was done in OpenSCAD, which makes it parametric and easy to modify.
Peristaltic pumps work by squeezing a length of tubing to push fluids. This mechanism is similar to how your intestines work. The pump provides an isolated fluid path, which is why they’re commonly used in medical and food grade applications. Like many products in the medical space, these pumps tend to be rather expensive. Being able to print one for your own projects could save quite a bit of cost.
The pump is based on [emmett]’s gear bearing design. One nice thing about this design is that it is printed preassembled. Pop it out of the printer, add some tubing, and you’re ready to pump fluids.
On top of the isolated fluid path, this pump gives accurate volume measurement. For that reason, we can imagine it moving booze for a robotic bartender build. After the break, a video of the pump moving some fluid.
Fantastic idea! I remember watching one of these years ago as my father had his dialysis treatments. It absolutely fascinated me. I just might have to go and print one of these to play with…
Definitely the cleverest design I’ve seen yet for a peristaltic pump. Does it really Just Work after 3d printing it on an FDM style 3d printer?
Now it just needs some motor mounts!
Depending on how hard you squish the first layer there might be some slight stickage on the first layer that needs to be broken free. other than that it works just fine.
The tolerance and overhang values in the openscad file may benefit from tweaking for different printers, but it should otherwise Just Work. Like sneakypoo mentions, a very thin layer will probably connect the gears right where they contact the printer bed, but pressing or turning them by hand should separate them easily. This extra fringe in the first layer can be removed by hand or with a small knife, or simply ignored (it will flake itself off after some use).
How the heck do you get it to print the separate gears in a way that they move freely right off the printer?
There’s simply a small air gap between each surface of the model. If your printer is set up properly it will not leave any strings between the moving parts and all will be well.
There are 3D printer with soluble supporting structure. You put everything in a lye wait for some hours and e voila (e.g. http://www.3dppvd.org/wp/2013/02/soluble-support-material/ ).
True but if you have your 3D printer properly dialed in these gears do not require support material. For more complex interlocking shapes, support material would probably be a definite boon. Pretty much any single extruder FDM style printer worth its salt should be able to handle this.
it’s even ok if the parts stick a little, you use a hammer drill to free the gears, and normal drill to spin it a little, let the gear friction grind down the stray bits of plastic.
Looks good. I recognised the gear bearing it’s based on straight away. If your looking for something to demo your 3D printer they’re perfect.
My old Canon MP160 printer had such a pump to pump the ink from the ink washing head to the absorber pads, though the design was much simpler: Just a drum, inside it the hose and a gear with a knob extending which squeezed the hose once each rotation.
I remember being fascinated by the peristaltic pump on the front of the Hobart dish washer I used at a dish washing job I had years ago. It pumped dish detergent into the washing chamber. I’ll have to make one of these.
Ok This just made my day :D
The gears themselves are awesome but the fact taht someone thought to make a few changes and *poof* peristaltic pump. Doesn’t hurt that I’ve been looking into buying/printing a peristaltic pump for a while because I’ve had the hankering to make a Italian Soda machine for a little while now.
Hay can I buy a couple of these from you?
This needs to go up on Shapeways if it’s not already!
This is why I frequent this site. I didn’t know what a peristaltic pump was before 5 minutes ago. Fascinating.
Just a dumb question here. How does one use this pump? Clearly power is intended to be applied to the central gear. Do you hold the outer part in your hand? Why not just print some mounting ears or something so that it can be bolted down? Just doesn’t seem very finished…
Clearly he just whipped up a quick proof of concept. It shouldn’t be hard to add a body mount along with a motor/servo mount to make it actually useful.
Also, if the files are available online, having just the minimum makes it easier for others to incorporate it into their own designs.
This first print was mainly a draft / proof of concept. Since no mount I design into it would fit every possible motor or use-case, I decided to just release the openscad design as-is and leave adding any application-specific mounting features as an exercise to the designer. There are a few recommended improvements mentioned in the blog post to be rolled in at some point, such as making the OD exact and adding a tubing retention feature (the tubing tends to very slowly walk through the mechanism without something to hold it in place).
This is damn impressive. Kudos sir.
Print a bunch of those, put some bottles and steppers – you end up with a bar-bot! If I finally get myself a 3d printer, after printing Joda’s head, this will definitly be my first project!
Looks good! A small clamp upstream of the pump will solve the creep problem. A quick point about accuracy though: Peristaltic pumps can be very accurate but frequently aren’t. The main problem is tube aging, which will cause drift. Periodically calibrating the pump is a good idea if you are concerned about drift. It is also worth checking the output of the pump each time you change the tube or move it along as cheap tube tends to have variable wall thickness leading to some quite big errors. I would be interested to know how much if any wear you get from pla gears, all the peristaltic pumps I have used were mostly stainless and ceramic.
This would work quite well as a swimming pool chlorine or acid dispenser. Set-up could be accomplished fairly easily.
Anyone want to have a crack at building and coding a few?
Well friggin done my man! There are endless applications for this. Liquid med distribution, alcohol distribution, precise chemical distribution, advanced aquarium setups…I can think of so many thing I’d like to use this for. Awesome job.
On the whole, I think its brilliant. I would love to see this used to create cheap dialysis machines to be used in poverty/disaster stricken countries. There’s a girl I work with that’s suffered from permanent kidney failure for a few years now, and she has to go for dialysis 2-3 times a week. I don’t know what that costs her, but I imagine, if somebody could design a complete 3D printed dialysis machine, with this pump at its core, she could probably save huge amount of money that could be better spent on the surgery she would need to get a kidney transplant. That and being able to do the dialysis at home would probably take allot less time out of her life, not to mention reduce the stress of the whole process.
The only thing I wonder, is whats the life of the bit of tube inside the pump itself. I would assume that the constant mechanical action must eventually break down the tube at the point were it bends. Of course it would be a simple mater of replacing the tube if you develop a leak, but it would be good to know the average life of the tube (depending on material used) so you could plan ahead with replacements.
Also, if you don’t have access to a 3d printer, its actually quite easy to build a Peristaltic pump with parts from your hardware store. A buddy of mine once made one to use as a sump pump in his basement. he used much larger tubing, I think it was 1 & 1/2 inch. and some beefy pulley wheels. thing worked great, and as far I know, hes only had to replace the tube twice in the three or so years its been in use.
The lifespan of the tube is hugely variable depending on the roller design, duty cycle, what you put in it and then the tube itself. High quality tubing for medical peristaltic pumps is quite pricey and for a homebrew dialysis you want everything sterile! It would be a big job.
Oh indeed, keeping things sterile would be the most important part. However, if we opted for lower quality tubing on the assumption that it would be thrown out after every use, then the life span of the tube wouldn’t be important. That would also deal with the sterility of the tube since you would always use a new one every time.
Even though the printed-in-one-part aspect is nice, specifically for this kind of pump it doesn’t make much sense as you have to pull the tube through the pump to set it up/take it down, compromising the sterility which is the whole point. Professional peristaltic pumps allows you to open the mechanism and place the tube inside without threading it through. I get that this is probably not meant for sterile applications anyways, and it is a cool print:)
@Tim It is disappointing to see a half done design float into the public arena, but it is true that we planned to give the design away given we saw no commercial value in this product as it can only practically be 3D printed.
I have posted a 3rd generation design here: http://www.thingiverse.com/thing:473655
It still had some tweaks that were needed.
I am looking for someone to design and print a small pump that fits inside a 1″ tube for a prototype. Can you help ? Thanks, Ralph
Does anyone know what material was originally used? I’m new to printing, and don’t want to assume. Although it looks like ABS?
most likely it is pla. PLA is somewhat self lubricating where abs is sticky. PLA is more than strong enough for this application
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