. Vacuum Forming Guide 1 Table of Content Introduction 3 Common Problems 31 Webbing/ Chill Marks/ Thinning 31 Applications 4 Chill marks / Thinning 33 The Vacuum Forming Process 6 Finishing and Trimming 34 Basic principles of vacuum forming 7 Clamping 8 Troubleshooting guide 41 Heating 8 Auto-level / Sheet Level 8 Contact 45 Pre-stretch ( Bubble) 8 Vacuum 9 Plug Assist - Only available on HD and TF Series 9 Cooling and Release 9 Trimming and finishing 9 Plastics materials and their characteristics 10 Overview typical plastics 11 Acrylonitrile Butadiene Styrene – (ABS) 13 Polystyrene – High Impact Polystyrene (HIPS) 14 Polycarbonate – (P.C. / LEXAN/ MAKROLON) 15 Polyethylene – (PE, HDPE, LDPE, PE FOAM) 16 Co-Polyester – (PETG / VIVAK) 17 Acrylic - PMMA – (Perspex, Oroglas, Plexiglas) 18 Polypropylene – (PP) 19 Polyvinylchloride – (PVC) 20 Mould Material and Mould Design 21 1- Modelling Clay, Plaster 22 2- Wood 22 3- Cast Epoxy Resins 23 4- Foam 24 5- 3D Printing/Rapid prototyping/Additive 25 manufacturing 25 6- Aluminium - Cast 26 7- CNC machined tooling board or model board 26 Male and Female Moulds 27 Mould Design: Basic Considerations 28 Draft Angles 28 Venting 29 Undercuts 29 Male and Female Moulds 30 2 Formech - Vacuum Forming Guide Introduction Thermoforming has been around for a very long Once you’ve got to grips with the contents of time, and has transformed the world that we live in. this guide, there will be just one question left It is a process that has helped to make items from unanswered; what are you going to make? the simplest of food packaging trays, to car interior parts, sets and costumes in Hollywood blockbuster movies, life saving medical equipment, and even components for space exploration. The possibilities of this production method are endless, with applications seen in almost every industry you can think of. Despite seeing and using thermoformed plastics every day, not everyone has even heard about thermoforming before, let alone had the chance to use it to design and manufacture something fresh out of their own imagination. ‘Thermoforming’ is used to describe any process Helmets Polycarbonate in which heat is used to shape and mold plastic, body formed on a although in this guide we will be talking specifically Formech 1372 about ‘vacuum forming’, which can certainly be considered part of the thermoforming family, only with some very important extras. The simplest description of the vacuum forming process is that of a sheet of plastic having heat applied to it until it softens, before being draped over a mold. A strong suction of air, or ‘vacuum’, is Mask DUESITH - Body formed on a Formech applied from below, attracting the soft plastic over 300XQ the mold to adopt its shape. Once cooled, the mold can be removed, leaving just a perfectly formed plastic component. A very simple process, but one which is hugely popular, effective, fast, and easy. The early 1900s saw the development of the first thermoforming machines. They were big, and took up a huge amount of space. We’re glad to say that things have changed a bit since then, and thermoforming equipment today can be so small it might fit on a school desk. Air conditioning units ABS - Body formed on In this guide we will be exploring the potential of a Formech 686 the Formech vacuum forming machine that you have available, covering all aspects of how to use it, what to use it for, how to produce your molds to form over, and all the tricks of the trade that go along with it. This document will be your one stop guide which you can refer back to at any point during a project that involves vacuum forming, to find all the answers, hints and tips you might be looking for. 3 Formech - Vacuum Forming Guide Applications Aeronautical Manufacturers Computer Industry > Interior Trim Panels, Covers and Cowlings Internal > Manufacture of Screen Surrounds sections for NASA Space Shuttle > Soft Transparent Keyboard Covers Enclosures Agricultural Suppliers and Ancillary Equipment > Seed Trays, Flower Tubs, Animal Containers, Clear Design Industry Growing Domes > Production of prototypes and Pre-Production Runs > Calf Milking Receptacles, Machines Parts > Lawn- > Prototype Concepts for other Plastic Processes mower Enclosures and Covers Education Architectural Model Makers > Training Aids for Students Studying Polymers and > Production of Miniature Parts for Architectural Plastic Processing Models > Prototypes Electronics Industry Automotive and Vehicular Industry > Manufacturing Enclosures for Specialist Electronic > Wheel Hub Covers, Ski-Boxes and Storage Racks, Equipment Wind Tunnel Models, Parts for All Terrain Vehicles > Anti-Static Component Trays Truck Cab Door Interiors, Wind and Rain Deflectors > Scooter Shrouds, Mudguards, Bumpers and Pro- tective Panels > Battery and Electronic Housings, Prototype and Mask HIPS - Body formed Development work on a Formech 300XQ > Utility Shelves, Liners, Seat Backs, Door Inner liners and Dash Surrounds > Windshields, Motorcycle Windshields, Golf Cart Shrouds, Seats and Trays > Tractor Shrouds & Door Fascia, Camper Hardtops and Interior Components Building and Construction Industry Radio Controlled Car - Body > Drainpipe Anti Drip fittings formed on a Formech 686 > Roof Lights, Internal Door Liners, PVC Door Panels, Producing Molds for Concrete Paving Stones and Special Bricks > Molded Features for Ceilings, Fireplaces and Porches Boat Building industry > Boat Hulls, Covers and Hatches Electrical Enclo- sures, Dashboards Chocolate industry Luggage acrylic - Body > Manufacture of Chocolate Molds for Specialised formed on a Formech 1372 Chocolates > Easter Eggs etc. and Packaging 4 Formech - Vacuum Forming Guide Applications Film and Media Industry Souvenir Industry > Manufacture of Costumes and Sets > Animation > Making parts for and molds to cast craft souvenirs Models and Mock Ups for Computer Simulation Sports Industry > Helmets, Guards and Gum Shields Furniture Manufacturing Industry Theatre > Chair and Seat Backs > Manufacture of Props, Sets and Costumes > Cutlery tray inserts > Kitchen Unit Panels and Storage Modules Toy Industry > Games, Action Figures, Packaging, Dolls, and Hospitals and Medical Applications Prototyping > Radiotherapy Masks for Treatment of Cancer Patients > Pressure Masks for Burn Victims > Prosthesis Parts > Dental Castings > Parts for Wheelchairs and Medical Devices for the Disabled Machinery Manufacturers > Fabricating machine guards and electrical enclo- sures Golf Car Parts Acrylic Capped ABS - Body formed Model Car and Aircraft Industry on a Formech 1500 > Production of bodies fuselages and other parts for models Museums > Variety of applications within Science and Natural History Museums Packaging and related Industries > Point of Purchase > Trays and Plates > Cosmetic Cases and Packages Props Acrylic Capped ABS - Body formed on a Formech > Electronics and Cassette Holders FMDH660 > Blister Pack Products, Skin Pack Products Food Trays, Cups and Fast Food Containers Plastic Sheet Extrusion > Testing and Sampling of Extruded Sheet Signage Industry > Exterior Signs Point of Sale Displays Sanitary Industry > Bathroom Fittings Acrylic capped ABS Kayak seat - Body formed on a > Bathtubs, Jacuzzis and Whirlpools > Shower Sur- Formech HD Series rounds, Shower Trays and Retrofit Shower Components 5 Formech - Vacuum Forming Guide The Vacuum Forming Process In its simplest form the process consists essentially greater detail later in this guide - see section Mould of inserting a thermoplastic sheet in a cold state and Mould Design.) into the forming clamp area, heating it to the de- sired temperature either with just a surface heater The typical process steps can be identified as or with twin heaters and then raising a mould follows: clamping, heating, pre-stretch, plug assist, from below. The trapped air is evacuated with the cooling with air and spray mist, release and trimmi- assistance of a vacuum system and once cooled ng. They are examined more closely under the sub a reverse air supply is activated to release the headings on page 8 and 9. plastic part from the mould. The process is shown in diagram on page 7. In its advanced stage pneu- matic and hydraulic systems complimented with sophisticated heat and process controllers allow high speed and accurate vacuum forming for those Cup cake POS display - Body heavy duty and high end volume applications. formed on a Formech 686 The thermoforming industry has developed despite two fundamental shortcomings. Many other ther- moforming processes use a resin base in powder or pellet form. Vacuum forming begins further down the line with an extruded plastic sheet which incurs an additional process and therefore an extra cost to reach this stage. In addition, there is generally an area of material which is cut away from the formed part which unless reground and recycled has to be considered as waste and accounted for in any costings made. However these problems have been invariably resolved by strict control of sheet quality and by clever mould design to minimise the amount of waste material. Throughout this manual you will find useful hints and techniques to assist in maximi- sing the potential from this process. Despite the above disadvantages vacuum forming Tray HIPS - body formed offers several processing advantages over such on a TF686 others as blow, rotational and injection moulding. Fairly low forming pressures are needed therefore enabling comparatively low cost tooling to be utilised and relatively large size mouldings to be economically fabricated