Did you ever think it would be possible to make a one-piece valve or pump?? Well let's see....
In this instructable I will show you how to 3D model and 3D print a one piece non return valve. You will also see how I developed the design into a one-piece pump for pumping liquid or air. The beauty of this design is it's ready to use straight off the printer, no support structure needed!!
The valve and pump can be 3d printed in NinjaFlex (or other flexible filament) in one piece.
The pump was not designed with a particular use in mind and was more of an exploration of possibilities with NinjaFlex filament. This was partly to see if a 3 leaf valve design could be 3D printed and to then develop it into a pump for pumping liquid etc.
The design was inspired by the aortic valve, one of 4 valves in the heart, some more info can be found here for those interested https://en.wikipedia.org/wiki/Aortic_valve
Step 1: What You Need
Access to Fusion 360, (or similar CAD package)
Access to an FDM 3d Printer capable of printing with flexible filament. (FDM stands for Fused Deposition Modeling) I used a MakerBot Replicator 2.
NinjaFlex filament or other flexible filament. https://ninjatek.com/products/filaments/ninjaflex/
Scalpel or sharp knife.
Step 2: 3D Modelling the Valve in Fusion 360
The valve was the first part I modelled. The following steps show how the part was modelled in Fusion 360.
1. Create a sketch on the top plane, as shown. This sketch contains lower sketch detail for lofting a leaf of the valve. You only need to loft one leaf so only create the sketch detail that is required. The sketch also contains detail to extrude the wall(1.6mm) of the valve. Centre the circle on the origin. It is best practice to model around the origin as it makes it easier to revolve pattern the leaf body thats needed later.
2. Offset a construction plane approx 12mm from the top plane.
3. Create a sketch on the offset plane containing the upper sketch detail needed to loft the leaf.
4. Loft lower and upper sketch details to make one Valve Leaf body
5. Use Circular Pattern to produce 3 leaf body's.
6. Extrude appropriate areas from sketch1 to make the outer wall of the valve, insure you select 'join' in the extrude dialogue, this will combine all bodies, so you should see only one body in the 'bodies' folder in the browser on the left.
7. Extrude the top surface to the valve up approx 3mm this will improve valve efficiency.
That is the valve finished and this can be printed in about 30min to 40min. It took me about 3 - 4 prints making small adjustments to the design in Fusion 360 to improve part strength and efficiency some of these can be seen in step 5.
To change any of the sketches you can right click the sketch in the browser, or on the history bar, and select 'edit sketch'
Changes to the outer wall diameter would reduces the force required to open the leafs.
Leaf thickness was tested at .4mm and .8mm (one or two passes of the .4mm 3d printer extruder).
0.8mm was stronger and less likely to fail.
0.4mm leaf thickness failed when printed at .3mm layer height with de-lamination between layers
0.4mm leaf thickness was successfully printed at 0.2mm however the leaves were not very robust.
Adjusting the tolerance between the leaves improved valve performance, reducing regurgitation, ease of flow and improved durability of the valve.
It's worth printing at this stage to make sure that the valve will function.
Step 3: Export and Setup for 3D Printing
There are a number of ways to export the part for 3D printing in Fusion 360. All of them will bring up the same dialogue box.
1. Right Click on the body you want to 3D print in 'Browser' menu on the left of the screen, and select "Save As STL".
2. 'File' - '3D Print' in the menu bar.
3. Use the 'Make' button on the panel at the top of the screen.
When the Dialogue Box appears make sure the body you want to Print is selected.
Set the mesh 'refinement', Medium should be fine for this model, Higher refinement will lead to higher file size and smoother surface.
You can choose to send to 3D Print Utility, or if un-ticked an STL file can be exported.
In this case I sent the file to Makerbot Desktop. There I had to orientate the part to make sure valve flow is pointing up.
Step 4: 3D Printer Setup & Print
I used some NinjaFlex that was left over form other print jobs. The material I used has a shore hardness of 85A. If this is your first time using NinjaFlex make sure your printer is capable of printing it. Some extruders may need modification to be capable of printing with flexible filaments.
When printing with any speciality filament its always worth going to the manufacturers website to check print settings, so here is a link for the filament I used https://ninjatek.com/resources/printing-guidelines...
My settings were:
15mm/sec for bottom layer and outlines
Reduce Retraction to about 0.7mm
It is always a good idea to measure your filament accurately with a callipers and set the filament diameter.
In my case it was 1.65mm
Preview and drop down the layers to make sure everything looks good.
Step 5: Testing, Modify & Re-Print
After initial printing it was apparent there was excessive regurgitation or back flow. Blowing through the valve in the opposite direction to normal flow will give a good indication of its capability. Ideally there would be no air getting through.
To reduce back flow I tried a few design changes,
Reduce the tolerance gap.
Changing the leaf wall thickness.
Extruding the top surface to the leafs by 2mm - 3mm.
I printed about 5 or 6 valves before finalising the design.
When printed some of the leaves fused during printing and needed to be cut with a scalpel. (This could be down to the calibration of the 3D printer I was using. X or Y axis belts might not be tightened to their optimum tension.)
Once happy with the valve design you can go on to model the Pump.
Step 6: Modelling the Pump
To model the pump you need to duplicate the valve and move it directly above the original. To do this in Fusion 360 you can simply copy and paste the body. Once pasted a triad appears that can be used to move the copied valve up into position. At this point you need to know what the limits of the Z axis on the 3D printer being used is. In my case the Z axis is 150mm so I moved the part 130mm as you also need to consider the 20mm height of the valve.
Create a sketch on the front or right plane as shown in the image above. I started by drawing a construction line from the centre top of the bottom valve to the centre bottom of the top valve.
From the centre point of this line draw a perpendicular line out. The dimension of this line will be the radius at the widest part of the pump.
Using the spline tool draw a two point spline as shown. Adjust the handles into a vertical position at both end points of the spline. This will produce curvature continuous surface that blends into the valve and when mirrored won't leave a sharp point where they meet.
Offset the spline and close the curves with a line to create a closed contour that can be revolved.
Revolve the contour making sure to create a new body, then mirror that body about its top surface.
You should now have 4 bodies that can be combined to create one body.
Your pump is now ready to export and 3D print, printing the pump will take approx 12 hours. Once printed you may need to use your scalpel to cut the leaves where they meet. Be careful not to split the leaf.
Step 7: To Sum Up...
It is possible to 3D print a functional valve and one piece pump that can be used for pumping air or liquid.
The one issue with the NinjaFlex is that it will degrade if exposed to water over a long period. However it does have good chemical resistance so if printing with this material the pump may be more suitable for pumping oil or fuel.
I have pumped water with this and was surprised that it worked so well. It's not perfect but that may be down to the setup of the 3d printer I was using which has possibly gone out of calibration on the X or Y axis.... time for an upgrade I think!!!
It would be great to hear your feedback and let me know what you are pumping....