Design and manufacture of sheet moulding compound process

Descriptions

To design, construct and install a production prototype Sheet Moulding Compound (SMC) manufacturing machine and SMC Trim moulding machine and process. To fully demonstrate that material / process equipment combination delivers a viable process, producing consistently high quality, void free SMC of closely controlled thickness and subsequently moulding the same material in a robust and repeatable hot curing process without the benefit / cost of matched metal tooling. The devised system must be capable of full scale up and industrial implementation.Objectives:The supplier must develop machinery (SMC manufacture and SMC moulding equipment) through design concepts to production drawings and manufacture and provide on-site installation and commissioning of prototype equipment along with validation of equipment / material combination in the final process .The supplier must fully define the processes - including optimum vacuum holding mechanism ( SMC to mould) in the curing cycle and optimum methods to achieve either overcoatability or “Final finish” trim formats.The supplier must ensure that the material and process works effectively across the range of Polyroof trim specifications foreseeable in the future for example, trims which may vary in thickness from 0.75 mm to 2.00 mm with equal control on uniformity and quality. The precise design of the SMC manufacturing machine must be such that quality is maximised and losses of VOC’s to atmosphere are minimised. The design of the machine must provide minimal resin paste spread and easy access to clean up. However the guards to facilitate this must not increase the footprint significantly or impede the easy use of the machine.Technical SpecificationBoth the SMC production stage and the moulding process will have a direct influence on the quality of the new format trims. The moulded trims from the new process must surpass the specification of the existing open moulded trim from a profile, weight and performance perspective as defined within Polyroof technical literature. A copy of this is available on request. Polyroof will review project performance against current trims and market competitors in respect of strength, robustness, fire retardancy, overcoatability and user friendliness.Basic elements / function of the semi-automated production of Sheet Moulding Compound (SMC).•Vacuum mechanism for holding of lower carrier film•Dispensing racks for 2 x carrier films•Traversing resin metering / dispensing reservoir capable of consistent and repeatable deposition of high viscosity resin based mixtures•Traversing upper film application & thickness calibration roller capable of eliminating air from the material surface and delivering thickness control of the finished compound to +/- 0.1 mm tolerance with full wet-out of the fibres.•Cutting mechanism for carrier films•Resin / additive pre-mixer and vessel.•System to dispense mix to doctor box.Basic function of the vacuum assisted, hot moulding of fibreglass Sheet Moulding Compound (SMC).•3 Metre long - heat transfer fluid filled male mould•Thermostatic control of mould temperature – accurate to +/- 1° C along length in the range 110-120°C•Effective circulation of heating fluid through the heater and mould•Vacuum system and holding mechanism to retain SMC on mould surface during processing.The new moulding process must surpass typical high intensity open mould hand lay up methods in terms of productivity ( target of < 10 mins processing time per part including loading and full cure) and must give significant improvements in cost, yield, waste & disposal, emissions and operative exposure. Product mechanical performance (tensile and flexural strength, modulus and elongation at break), aesthetics and receptiveness to adhesion of subsequent unsaturated polyester based coatings / treatments without the need for further solvent or abrasive processes must also be superior to the current standard .Key to the moulding process will be a system for accurate placement of the SMC “slug” onto the mould and holding in place while the vacuum membrane is brought to bear. Low cost and low environmental impact films must be specified to protect the mould from rapidly hardening resin adhering and interfering with the next cycles. The loading and vacuuming mechanism must be quick and robust – capable of being unloaded and re-loaded in approximately 90-120 seconds. A non-aqueous heating fluid must be used to allow for moulding at 110oC-120°C . The moulding process must allow for the introduction of some surface texture and colour .