# Plate cam, constant acceleration (parabolic) rise 12 mm, base circle R20, for a flat-faced follower

> What profile does a constant acceleration (parabolic) plate cam have?

- Category: Hardware › Mechanism parts
- Kind: Modern device
- Basis: Xem Studio design following Brown's figure (1868); true size, no printing allowance
- Page: https://xemstudio.com/objects/plate-cam-parabolic-flat-r20-h12/ · JSON: https://xemstudio.com/api/geometry?object=plate-cam-parabolic-flat-r20-h12 · Plain text: https://xemstudio.com/objects/plate-cam-parabolic-flat-r20-h12/sheet.txt
- License: dimension sheet CC BY 4.0 (Xem Studio); linked files under their publishers' licenses
- Use in every chat: add https://xemstudio.com/mcp as a connector (https://xemstudio.com/use-with-ai/)

## Overall (mm)

| length | width | height |
|---|---|---|
| 52.0 | 52.0 | 6.0 |

**Exact dimensions.** True size, with no printing tolerance added.

## Notes

- Disc cam (6 mm, Ø5 bore) for a radial flat-faced follower on a 20 mm base circle: rise 12 mm over 120° with constant acceleration (parabolic) motion, dwell 60°, return over 120°, dwell 60°.
- Profile computed point by point (720 points) from the displacement law: envelope of the flat face: contact at x = ds/dθ from the follower's axis.
- Xem Studio design following Brown's figure; true size, no printing allowance (apply your own to the mating features).

## Sizes

| dimension | value |
|---|---|
| base circle | R20 |
| rise | 12 mm over 120° |
| dwells | 60° high, 60° low |
| law | constant acceleration (parabolic) |
| bore | Ø5 |
| thickness | 6 mm |

## Where the files are

- Henry T. Brown (1868, public domain): [Five Hundred and Seven Mechanical Movements — scan on archive.org](https://archive.org/details/fivehundredseven00browiala) — web — Publisher's page; dimensions are facts
- 507movements.com: [Brown's movement No. 138: figure, his text and an animation](https://507movements.com/mm_138.html) — web — Publisher's page; dimensions are facts
- Xem Studio: [drawing](https://xemstudio.com/objects/plate-cam-flat-follower-mechanism/) — web — Publisher's page; dimensions are facts

## Free STEP/STL (1 parts, CC BY 4.0, Xem Studio)

Index: https://xemstudio.com/files/hardware/plate-cam-parabolic-flat-r20-h12/index.json

- plate-cam-parabolic-flat-r20-h12: [STEP](https://xemstudio.com/files/hardware/plate-cam-parabolic-flat-r20-h12/plate-cam-parabolic-flat-r20-h12.step) · [STL](https://xemstudio.com/files/hardware/plate-cam-parabolic-flat-r20-h12/plate-cam-parabolic-flat-r20-h12.stl) — cam, z 0..6, follower on +Y at cam angle 0

## Questions

**What profile does a constant acceleration (parabolic) plate cam have?**

Disc cam (6 mm, Ø5 bore) for a radial flat-faced follower on a 20 mm base circle: rise 12 mm over 120° with constant acceleration (parabolic) motion, dwell 60°, return over 120°, dwell 60°.

## Fits with

- [Plate cam with flat-faced follower (constant acceleration (parabolic) rise)](https://xemstudio.com/objects/plate-cam-flat-follower-mechanism/)