Level 7 Plastics Inc. · Jan 2019 – Oct 2021

Heated sheet press for recycled HDPE (compression moulding)

Heated hydraulic press that compression-moulds shredded HDPE into large sheets, the stock for Level 7's hangboards and furniture. Still in service with the university research group.

My role: Designed the press, iterating from an in-house design to an upgraded variant of the Precious Plastic sheet press; built and wired it with the team.

The sheet press: stainless top, aluminium-extrusion frame, hydraulic jack underneath, and the control panel with six temperature controllers and a main isolator.

The press frame modelled in ANSYS for my finite element analysis course project.

ANSYS static structural result for one frame corner bracket: equivalent (von Mises) stress.

Highlights

Designed a heated sheet press for recycled HDPE: 20 ton air-over-hydraulic press with machined-aluminium heating blocks (cartridge heaters, PID controlled) running at about 185 °C, built from steel plate, welded brackets, and aluminium extrusion, all bolted.
Pressed sheets fed hangboard and furniture production; the moulds have never needed replacement.
Simulated the stresses in the sheet press structure under load in ANSYS as the project for my finite element analysis course.
Solved parts sticking in the mould by selecting a high-temperature mould release.

My contribution

I designed the press, iterating from an in-house design to an upgraded variant of the Precious Plastic sheet press, then built and wired it with the team.

Technical details

A 20-ton air-over-hydraulic press provides the force. Heat comes from machined-aluminium heating blocks with cartridge heaters, held at about 185 °C for HDPE by PID controllers. The frame is steel plate, welded brackets, and aluminium extrusion, bolted together. The mould has never needed replacement.

Lessons learned

Parts occasionally bonded to the mould; specifying a high-temperature mould release resolved it.

Tools and processes

Materials: HDPE feedstock; steel plate and welded brackets; aluminium extrusion; machined aluminium heating blocks
Loads: 20 ton hydraulic press
Processes: compression moulding; PID temperature control; machining (heating blocks); welding; bolted assembly
Tools: 20 ton hydraulic press with pneumatic pump; cartridge heaters; PID controllers; high-temperature mould release; ANSYS (FEA course project)

Key figures

Press force	20 ton
Moulding temperature (HDPE)	about 185 °C

Part of Level 7 Plastics Inc..