Intro: Cylindrical Pin Bed Forming Tool
Rather than just forming between two parallel surfaces, this smaller cylindrical version of my Pin Bed Forming Machine works in the round. The pins can be directed towards the interior or exterior of the cylinder simply by how the sheets are inserted into the engraved wood base. The pins can push material inwards or expand materials outward. The sheets can be arranged anywhere along the engraved base depending on the size of the object intended for forming.
Step 1: CNC Base
Use a jointer and planer to prepare two boards of maple. Cut down the board into six pieces to laminate a perfect square.
Model the engraving pattern and the wood base in Fusion 360. Select the bottom face of the engraving paths in CAM and set your overall depth and step down. The pattern of the engraving will act as slots for each sheet of aluminum. The sheets are 1/4 inch thick, so a 1/4 flat end mill is selected as the tool.
Step 2: Which Fabrication Method Is Faster? More Efficient?
I tested two methods for making holes, by hand and by high speed machining, to determine which process would take less time. The one that requires manual labor or the one that involves programing and setting up a machine.
Hand drilled holes & threads:
- Lasercut a template to center mark all your holes.
- Clamp the acrylic template as the first layer on top of your four aluminum sheets
- Clamp the stacked sheets to the manual drill press above a spoiler board
- Make each hole by hand, use lubricant
- Power tap all the holes by hand
- Take breaks
Step 3: Machining Holes
HAAS machined holes & threads:
- Model the final part in Fusion 360. (four sheets of aluminum with holes stacked on top of a spoiler sheet = 1.25 inches roughly)
- Pre drill and tap three 8-32 holes on the drill press to hold the sheets together with 8/32 screws
- Place the stacked sheets on the HAAS using a Kurt Jaw Vise
- Run a setup for drilling and tapping each hole while skipping the holes where the screws are.
- Make sure your roll tap is long enough to machine through all four layers (this setup partially failed because I was relying on the manual lathe to adjust my tool, however the tool body was such a rare diameter that none of the collets for the lathe could hold it properly. This meant that I could only machine threads through two layers of aluminum rather than all four)
Step 4: Finishing
Sand and finish your engraved maple work surface with poly-acrylic. Sand blast each aluminum sheet for a clean finish. Twist each screw through the perforated sheet and secure in place with an acorn nut. Use a power drill to speed up the process.
Step 5: Voila!
Now you have a cylindrical pin bed forming machine. Activate as many screws, as many panels, and in whatever pattern you wish, using whatever material you want to manipulate. I might start by experimenting with a thrown or cast clay vessel.