A mould insulation sheet is generally mounted between the mould clamping plate and the machine platen. Depending on the mould design, insulation may also be placed between the ejector housing or mould base and the moving platen. Final placement should follow the mould drawing, clamping arrangement and machine manufacturer’s requirements.
Resin insulation sheets are generally manufactured from strong thermosetting resins and offer reliable insulation at typical injection-moulding temperatures. Glass-fibre or glass-reinforced sheets contain structural fibres that usually provide higher compressive strength and can operate at higher maximum temperatures. Selection depends on the actual mould temperature and clamping load.
Yes. Modern mould insulation sheets are manufactured from safe, asbestos-free polymer and composite materials. They conform to current environmental and workplace safety requirements and provide the thermal separation previously managed by older asbestos-containing materials.
The official page lists maximum operating temperatures of 200°C for resin sheets and 250°C for glass-fibre sheets. Operating above the specified limit can cause the sheet material to soften, degrade or lose compressive strength, increasing the risk of plate movement or thickness reduction under load.
The sheet sits in the primary load path and must transmit the entire machine clamping force without compressing, crushing or yielding. If the insulation compresses under load, the clamping force across the mould may become uneven, potentially causing flash, core shift or reduced plate alignment accuracy.
Yes. A thicker insulation sheet provides a larger thermal barrier and generally reduces heat transfer more effectively than a thin sheet. However, increasing the thickness takes up additional machine daylight and changes nozzle penetration depths, so thickness should be specified carefully during mould design.
Thicknesses between 5 mm and 10 mm are common for standard injection-moulding applications, as they offer a good balance of thermal resistance and space efficiency. Thicker boards may be selected for very high-temperature tools or hot-press applications, provided the machine clamping unit has sufficient daylight.
Die-casting tools operate at temperatures that can far exceed the 250°C maximum rating listed for standard glass-fibre or resin sheets. A standard injection-moulding sheet used on a die-casting tool will burn, smoke or fail under clamping pressure. A suitable high-temperature alloy or ceramic-based material must be verified before use.
Yes. By separating the hot mould from the cold machine platen, insulation sheets reduce the heat drain into the machine structure. This can lower the energy required by mould temperature controllers or internal heating elements to maintain the set temperature, particularly in continuous hot-mould processes.
Yes. Because the heating system does not waste energy heating the large mass of the machine platen, the mould can reach its required operating temperature faster and stabilise more quickly. This can reduce non-productive waiting time during machine setup and material changeovers.
Insulation sheets are typically fastened directly to the mould clamping plates using countersunk screws. The screw heads must sit fully below the sheet surface so they do not touch the machine platen. Uneven or protruding screw heads will concentrate clamping force and cause the sheet to crack.
Yes, the insulation sheet should match or closely follow the outer profile of the mould clamping plate. This ensures full support for the clamping load and prevents any exposed hot mould surfaces from transferring heat to the platen. The sheet must not interfere with machine tie bars or clamps.
Yes. A large clearance hole must be machined in the centre of the injection-side insulation sheet to allow the locating ring to pass through and seat into the machine platen correctly. The hole should provide sufficient clearance without weakening the central area of the sheet.
The locating ring typically fastens through the insulation sheet and directly into the steel mould plate. Sometimes a deeper or specially stepped locating ring is required because the insulation sheet adds thickness between the mould and the platen. The ring’s projection into the platen bore must remain adequate.
Yes. If the insulation sheet is mounted across the rear of the mould base, clearance holes must be machined to allow the machine knockout or ejector rods to pass through and actuate the mould’s ejector plate. The holes must be aligned accurately to prevent the rods from rubbing against the composite material.
Yes. Standard tools can drill, mill and cut resin or glass-fibre sheets. However, machining composite materials produces fine, abrasive dust. Proper dust extraction, personal protective equipment (PPE) and suitable sharp carbide tooling should be used. Ensure all machined edges and holes are deburred before installation.
New resin-based composites may release a mild odour when first brought up to operating temperature due to the final curing of binders. This should subside after the initial heating cycle. If the smell persists or the sheet shows discolouration, check that the mould temperature has not exceeded the material’s rated limit.
Cracking is typically caused by uneven clamping forces, unsupported plate areas, debris trapped between the sheet and the platen, protruding mounting screws, un-chamfered clearance holes or mechanical impact during mould handling. The sheet must have flat, clean support on both sides to safely handle high clamping tonnage.
Continuous exposure to leaking hydraulic oil, mould coolants, rust preventatives or aggressive solvents can degrade some resin binders over time, reducing compressive strength or causing the sheet to swell or delaminate. Maintain a clean, leak-free mould environment to maximise the life of the insulation.
Replace the sheet if it is visibly cracked, flaking, deeply scored, permanently compressed, oil-soaked or if the mounting-screw holes have enlarged. A damaged sheet can compromise clamping alignment, leak heat and cause the mould to rock slightly under injection pressure.
Unlike steel plates, composite insulation sheets are relatively brittle. Bumping the mould edges, resting the mould unevenly on the sheet or lifting the tool by features that bear against the insulation can chip or crack the material. Rest the mould squarely on dedicated support feet or steel parallels when it is outside the machine.
While technically possible if the dimensions match exactly, reusing an old sheet is not recommended. The sheet may have taken a slight compression set from the previous mould’s load profile, and new mounting holes could intersect old ones, weakening the board. We suggest fitting a new, correctly machined sheet for a new mould.
Thermal conductivity defines how much heat passes through the material. A lower value means better insulation. However, an insulation sheet must be selected on a balance of low conductivity, high compressive strength and appropriate temperature resistance. The lowest conductivity material is useless if it crushes under clamping pressure.
No. The official page states that the material has excellent electrical insulation properties. This is an added safety benefit for moulds equipped with hot-runner systems, internal heaters or electrical sensors, as the sheet helps prevent stray currents from tracking to the machine platen.
Yes. While standard rectangular blanks are available, buyers can request sheets pre-machined to match the mould outline, complete with the central locating-ring hole, ejector rod clearances and countersunk mounting holes based on an approved tool drawing.
