Based on contributions by Matthijs, How-to.
Standard off-the-shelf suction cups are made for flat or simple curved surfaces. If your object doesn’t have a flat surface — and no standard cup gives a good seal — you can design and 3D-print your own. This covers the general design principles and the concrete steps, using an example of picking up ampoules by the tip.
What you need
- 3D printer and PLA filament (no need for a flexible filament like TPU/TPE — PLA works fine for this)
- CAD software
- The exact dimensions of the object you’re picking up (or its governing standard, if any)
- A way to test the suction cup on the actual object (by hand and, once close, on the robot’s suction mount)
General design principles
Before you start designing, keep two rules in mind for any end-effector design, suction cups included:
- Simplify the design as much as possible.
- Don’t engineer something that doesn’t need to be there — added complexity is a major time sink and a common source of failure.
Steps
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Measure the object’s important dimensions. Many objects have standardized dimensions you can look up instead of measuring by hand — search
ISO/NEN/DIN [name of your object](e.g. “DIN Ampoules”). -
Print small test versions first. Start with the smallest test prints you can — you’ll need several iterations to get the design right, and small prints are fast and cheap. Once you’re confident the sealing geometry works, figure out how to connect it to the end effector.
-
Don’t hesitate to make many test prints. This is R&D — expect to iterate.
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Use PLA, not a flexible filament — it seals well enough for this purpose without needing TPU/TPE.
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Maximize the sealing contact area where the cup meets the object, while still maintaining a good seal — a larger contact area gives a stronger lifting force (
p = F/A, soF = p Ă— A). -
Add a chamfer sized to your tolerance range, so the cup can still form a good seal across the full range of dimensional variation in your object. In one build, a 2° chamfer was sufficient.
Related
- How to choose and use suction cups for picking up objects — choosing and using standard, off-the-shelf suction cups
Rewritten and consolidated (Sept 2026) from the original student how-to’s: How to design suction cups for a very specific object, Design a robot’s end effector, Design and use tolerances in 3D design.