A hand-cranked slicer we're designing to cut pizzas before they're boxed. It leaves the middle uncut, so the pizza goes through the machine in one piece and each slice pulls off by hand after the bake.
Slide the pizza back until it touches both stops. That centres it under the blades.
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The cut plan, steps and spec below still describe the design.
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Every blade stops 30 mm from the middle, so the slices stay joined by a Ø60 mm disc of uncut base. That disc keeps the pizza in one piece in the box, through the machine and in the oven. When it comes out, a slice tears free along two short seams with a light pull, so customers don't need a knife or a cutter wheel at the kiosk.
The blades run 9 mm past the crust, so the edge is always cut through, even when a pizza sits slightly off-centre or comes out a little over 254 mm.
From the board to the customer's first slice.
Set the pizza on the board and slide it back against the two stops. They centre a 10-inch pizza under the blade head, so the uncut disc lands in the middle.
Turn the crank on the right. Through a 3:1 gear pair and a rack and pinion at each side, about 2¾ turns lower the head 90 mm. Both racks share one shaft, so the head can't tilt.
The sprung centre pad meets the pizza first and holds it flat. The blades follow, cutting down to the board from the crust in to 30 mm from the middle.
Crank back the other way. The pad keeps pressing until the blades are clear, so the slices don't stick to the blades and lift with them.
Lift the pizza into its box on the wire grill and close the lid. It's still one piece, so it handles like an uncut pizza in the machine.
After the bake, the customer opens the box and pulls a slice. It tears off the centre along its two short seams.
For a first prototype.
| Pizza | Up to 10 in (254 mm), the machine's limit |
|---|---|
| Slices | 8, with 6 or 10 by swapping the blade head |
| Uncut centre | Ø60 mm, so each seam stays joined for 30 mm |
| Blades | 1 mm hardened stainless, 60 mm deep, from 30 mm out to 136 mm radius, welded to an outer ring and a centre hub |
| Centre pad | Acetal disc, Ø50 mm, sprung, resting 6 mm below the blade edge |
| Drive | 140 mm crank, 3:1 spur gears, cross shaft with two 16-tooth pinions, one rack each side |
| Stroke | 90 mm in about 2¾ turns, with 68 mm clear above the pizza at the top |
| Leverage | About 26:1 before friction |
| Board | 15 mm food-grade polyethylene, lifts out to wash |
| Frame | 304 stainless, two Ø28 mm guide columns |
| Size | About 615 × 380 mm on the bench, 540 mm tall |
Open questions we'll answer before building one.
This is a design concept. The dimensions are a starting point for a prototype, not a manufacturing drawing. Back to resources