Plate cam, constant acceleration (parabolic) rise 12 mm, base circle R20, for a flat-faced follower — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/plate-cam-parabolic-flat-r20-h12/  (CC BY 4.0)
Basis: Xem Studio design following Brown's figure (1868); true size, no printing allowance
Catalog version: 2026-10-20

Overall (mm): length 52.0, width 52.0, height 6.0
- 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).

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

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

Free files (CC BY 4.0, Xem Studio; STEP + STL, 1 parts): https://xemstudio.com/files/hardware/plate-cam-parabolic-flat-r20-h12/index.json
API: https://xemstudio.com/api/geometry?object=plate-cam-parabolic-flat-r20-h12