Digital Modelmaking

Laser Cutting, 3D Printing and Reverse Engineering

Helen Lansdown

• Publisher: Crowood
• Year: 2019
• ISBN:
  9781785005862
• Topic: Design
• Subtopic: Produktdesign

Digital manufacturing has become an intrinsic part of the modelmaking profession, so today's practitioner must be skilled in both traditional hand-making techniques and digital technology. Relevant to a wide variety of creative industries, including film and television, theatre, architecture and product design, Digital Modelmaking offers a comprehensive insight into the manufacturing processes and technologies used within contemporary modelmaking. Each chapter contains an in-depth explanation of each topic, presents examples of how each process is used and includes case studies from professional modelmakers and students. Topics covered include: making models using a laser cutter, 3D printer and CNC milling machinery; generating 3D digital data using a 3D scanner and photogrammetry; two-and three- dimensional drawing software such as CAD; designing models for digital manufacturing; selecting materials based on their suitability for modelmaking; combining traditional hand-making skills with digital manufacturing; painting and finishing models, and finally, moulding and casting using silicone and resin. This invaluable book will be of great interest for students, young professionals and everyone with a passion for design and making. It is superbly illustrated with 234 colour photographs and 32 line artworks giving numerous examples of the design process. Helen Lansdown has worked professionally as a modelmaker and designer for thirty years and is a lecturer at Herefordshire University teaching on the Model Design programme.

1

FUNDAMENTAL MODELMAKING SKILLS

Model by Paulina Grenda. PAULINA AND SONKE FALTIEN

INTRODUCTION

The focus of this book is digital technology in modelmaking, but models are made using a combination of manufacturing methods, various workshop equipment, different materials and handmaking techniques. In this chapter, you will learn some of the fundamental skills used by modelmakers. All of the techniques, materials and products listed here have been used to make the models in this book. It is only possible to give very general advice in this section; the reader is asked to refer to other books for more in-depth information. The digital manufacturing methods featured in this book are extremely useful but understanding how to construct a model by hand using basic workshop equipment provides a practitioner with an invaluable understanding of materials, how they cut, shape and glue. It is this understanding of materials, hand skills and finishing techniques, used in conjunction with digital technologies, that make a modelmaker a specialist craftsperson.

GENERAL ADVICE

Health and Safety

This subject could form the entire contents of this book and still not adequately address the wide variety of health and safety issues faced by modelmakers. We use hand tools and machinery on a daily basis and work with harmful chemicals, including resins and solvent paints. It is the responsibility of the reader to ask for instruction, read the relevant documentation, thoroughly understand the health and safety instructions for every product, machine and process that they use, and take the necessary steps to protect themselves and those around them.

When using machinery, each person must understand the correct procedure and safety regulations for each piece of equipment; if they don’t, they must read the safety instructions and ask their line manager or teacher for training and safety instruction. Polyurethane, resins, solvent paints and most glues are hazardous, and some people develop a lifelong sensitivity to them. At the very minimum, tie back long hair, wear a dust mask (a respirator for solvent paints and resin), wear safety glasses and disposable rubber gloves, and make sure to cover all exposed skin, including the arms and hands. The intent of this book is not to be a manual for health and safety but as this is such a vital aspect it would be irresponsible not to highlight its importance.

Toolkit

Most modelmaking companies will have a fully equipped workshop of tools, but it is a good idea for a practitioner to have a small personalized toolkit. A basic modelmaker’s toolbox will include: a notebook, pencils (including a propelling pencil), eraser, a pair of compasses, scissors, a 300mm steel ruler, a scale ruler, circle cutter, tape-measure, a scalpel handle and blades (10a Swan and Morton is a good choice), a Stanley knife and cutting mat, a combination square, an engineer’s square, Vernier callipers, sculpting tools, files, needle files, pliers and screwdrivers, a set of drills from 1mm to 6mm, hacksaw, cordless or hand drill, hammers, clamps, a Dremel and a vice. Basic health and safety equipment should include: disposable rubber gloves, safety glasses, a dust mask and a respirator for spraying solvent paint, and moulding and casting.

A range of tools used by modelmakers, including: a cutting mat, scale ruler, circle cutter, steel rulers and a scalpel handle and blades.

A range of tools used by modelmakers, including: a drill set, files, clamps, engineers squares and vernier callipers.

Workshops

The equipment in a modelmaker’s workshop will vary, depending on the specialism of the company. A typical set up will include bandsaws, pillar drills, circular saws, disc, bobbin and belt sanders. Larger machines are likely to include a vacuum former, laser cutter, manual and CNC milling machines, CNC routers and lathes. Also, moulding and casting equipment, including a vacuum casting machine and a spray booth.

PRODUCTS AND PROCESSES

Glues

The glues are listed alphabetically, not in order of importance. Always read the health and safety instructions for each product.

A range of standard glues including dichloromethane and two-part epoxy.

Cascamite This is a powdered glue that is mixed with water to create a paste. It will glue wood, it produces a very strong joint and is typically used for exterior joinery.

Contact Adhesive A common brand is Thixofix and it is used to glue wood, MDF, veneer, laminate and rubber. This glue is applied to both surfaces and left to dry before fixing together.

Cyanoacrylate (Super Glue) This is a general-purpose glue, but the resulting joint is brittle and will fracture under force. It can ‘bloom’ when there is moisture in the air, which results in a whitish powder, but there are low odour and low bloom products. Super glue will not produce a crystal clear joint, so it should not be used to glue clear models. It will stick different types of material together, e.g. plastic to metal or wood, but two-part epoxy is usually a better choice in this instance.

Dichloromethane This is used to glue plastics like acrylic, styrene and acrylonitrile butadiene styrene (ABS). It is water thin and applied with a brush. A brand name for this product is Plastic Weld. Tensol 12 is a similar product that includes dichloromethane, but it is thicker and will fill small gaps between the two pieces of material.

Glue Stick A common brand is Pritt Stick and it is used for card and paper, including fixing paper templates on to material for cutting on a bandsaw or disc sander.

Hot Glue This will provide a temporary fix between two parts. It is useful for attaching a model to a spray stick. Further information on sprays sticks is in the finishing section of this chapter.

Latex Glue A common brand is Copydex and it is used to glue porous materials, e.g. fabrics and paper.

Polyurethane Glue A common brand is Gorilla Glue. This adhesive is activated by water and is used to bond many different types of material, including wood, stone, foam and glass.

PVA (Polyvinyl Acetate) This is water-based and used to glue wood, MDF and wood veneer. It will also provide a temporary fix between two blocks of styrofoam. When diluted, it is used to seal the surface of porous materials.

Spray Glue This has many uses, including fixing paper templates on to material for cutting on a bandsaw or disc sander.

Two-Part Epoxy A common brand is Araldite. This adhesive produces a strong bond between two different types of material, e.g. it will glue wood to plastic. It has two parts, A and B, and because it is thick, the two surfaces do not need to be entirely flat. It cures quite quickly, 5 to 10min depending on the type, and because it does not glue immediately, it allows plenty of time to apply the glue and accurately position the two pieces. A tip is to tape or clamp the two pieces together until cured.

Sketch Models

Sketch models are helpful in the early stages of the design process, for client meetings and to convey an idea in a group discussion. Sketch models are quick to construct and are not precious objects or expensive to make; they allow a designer freedom to try out an idea, discard it and move on to their next design. Sketch models are usually cut out by hand in low-cost materials, e.g. card, foamboard and polystyrene foam.

Foamboard has a foam core sandwiched between two pieces of card; it is light and easily cut with a scalpel. It is manufactured in various thicknesses, including 3mm and 5mm, and when scored with a knife, it will bend into curved shapes. There are different types of foamboard, some are made of polystyrene clad with thin card, which will melt under contact with solvent-based glues. Hot glue, a glue stick, double-sided tape and PVA are good choices for sticking foamboard.

A handmade sketch model of a door; the purpose of this model was to establish the level of detail needed for a 1:15 scale model.

Styrofoam looks similar to lightweight polyurethane modelling board, but it isn’t. It is essential to understand that it does not behave in the same way or indeed glue with the same products. This material is cheap (used for building insulation) and is cut and shaped by hand using knives, saws or a hot-wire cutter. It will melt when heated and cannot be glued or painted with solvent-based products. Water-based glue, including PVA, will stick two parts together, but not particularly well. The best option is to make the model from a single block, where po...