Processes and Production - Deforming and Reforming

Processes and Production - Deforming and Reforming

You need to be able to give examples and make good choices about how to shape for and join your materials. This could be tested in the exam and should be talked about using technical terms in your coursework.

Paper and card:

Cutting – Scissors and craft knives are used to manually cut paper and thin card when detail is needed. If multiple complex shapes need cutting you could use a CAD drawing and a laser cutter. Layers of material and thick card can have straight lines cut with a guillotine. Repetitive shapes can be cut using a specially made metal die, which, when high pressure is applied, can cut through many layers at a time.

Creasing and scoring – Shapes can be scored into card or paper to help them neatly crease (fold).

Perforating – Perforated paper is easier to fold or tear off, used in raffle tickets or cheque books. By hand a rotary cutter can be used with the perforations around the cutting edge. Perforations can also be added to dies or cut with a laser cutter.

Timber:

Cutting – Several types of cutting tools are available for different ways of cutting wood. A hand saw can have a wide blade for cutting straight lines or a thin blade to allow cutting around a bend. Machine tools for cutting wood include circular saws for straight cuts in sheet wood, band saws can be used for straight or curved cuts, jigsaws are electric hand tools with interchangeable blades for different surfaces. They are quicker and more accurate than by hand but require stringent health and safety rules and dust extraction.

Joining – Wood can be joined with a variety of hardware such as screws or with wood joints depending on the shape you’re making. Frames would use mitre, dowels and mortise and tenon joints. Box shapes would be joined with but, lap, dovetail and comb joints.

Drilling – Drilling wood can be done with a hand drill, brace drill, pillar drill or power drill. Basic twist drill bits can create small holes, flat bits are able to drill larger holes and hole saws can make bigger holes. Countersink bits cut a dip for screws to sit in.

Chiselling – Hand chisels are extremely sharp, flat headed tools for cutting away material when tapped with a mallet. They have different shaped heads for removing material. Electric routers perform the same task. They can produce grooves, slots and shaped edges.

Sanding – Sanding by hand would be with abrasive sand paper, different levels of coarseness sand smoother and smoother surfaces. Files have small metal teeth which are abrasive and able to shape wood, different sizes and shapes can smooth uneven edges. Band sanders and disk sanders are quick and accurate ways of sanding edges by pushing against them. Palm sanders are small electric sanders which move sandpaper at high speed.

Planing – Bench planes have an angled blade which shaves off a layer of wood each time it passes. A power planer works in the same way but is less effort.

Wood can also be shaped by gluing thin veneers together and holding them in shape with a vacuum until the glue is dry. This is called laminating.

Metal based material:

Cutting – Hand shears or power shears can cut sheet metal. A hack saw is used to cut metal rod. Band saws with a strong blade can also cut rod and sheet material.

Drilling – Metal can be cut with the same tools as wood but with stronger drill bits made out of high speed steel. Quicker and accurate holes can also be cut with a lathe or milling machine. Holes can be tapped and threaded to screw bolts in.

Turning – Centre lathes spin metal rod at high speed which can be shaped using hand tools. This can produce shape that is very accurate and smooth.

Milling – Milling machines remove a thin layer of material at a time making surfaces perfectly flat. The cutting tools are pre-set to cut at particular depths.

Casting – Molten metal is poured into a mould and cooled. Once removed from the mould it is trimmed and polished.

Welding – The strongest way of joining metal. An oxyacetylene torch produces a high temperature flame which heats both sides of the metal and a welding rod to fill the joint.

Polymers:

Cutting – Hand cutting a polymer would be with a coping saw, the thin blade allows shapes to be cut. A jigsaw with a special blade can be used to cut sheet plastic as can a band saw.

Drilling – Drills and drill bits suitable for cutting wood are also suitable for polymers.

Casting – Molten plastic can be forced into a mould, cooled, removed and trimmed. Injection moulding forces molten plastic into a mould.

Forming – Heated sheet can be sucked over a mould to be vacuum formed or blown into a mould for a blow moulded shape (like a bottle).

Extrusion – Heated polymer is forced out of a nozzle to create long rods.

Printing – 3D printing enables molten plastic to be layered up to make a computer aided design.

Joining – Polymers can be joined by liquid solvent cement, superglue or epoxy resin, it can also be welded using high temperature and plastic welding rods.

Textiles:

Sew – Textiles can be joined by hand stitching with a needle and thread, this is accurate but slow and weak. Faster and stronger stitching would be done on a sewing machine. Overlockers are able to edge and sew at the same time, giving strong seams (joins) and hems (edges).

Cutting and forming – Fabric shears are big, sharp scissors which can cut easily through fabric. Multiple layers can be stamped, laser cut or (if plastic based) with a heating element.

Pleat – Pleating is a way of shaping fabrics, folding the material into a zig zag gives a neat, decorative effect. It can be ironed in place and sewn across the top to hold its shape.

Gather – A row of stitching can be sewn across a fabric and when pulled draws the fabric together in a ruffle.

Quilting – Quilting is a fabric – wadding – fabric sandwich which is then sewn through to create a padded but decorative effect.

Piping – Folding fabric over cord and stitching close to the edge creates piping. When the piping is sandwiched into a seam it can make a strong decorative edge. It’s often used in upholstery to protect and strengthen edges.

Electronics:

Cutting – Laser cutting is the best way of cutting circuit board accurately using a CAD drawing.

Drill – Printed circuit boards (PCB’s) need to have tiny holes drilled into them to allow components to be soldered on. The holes need to be drilled at perfect right angles so the drill is held in a stand.

Solder – Soldering connects components together with a conductive material. Metal pins and wires are put onto the circuit board and permanently joined by hot solder; care must be taken to not let the solder joints touch as they will cause a short circuit. Automated soldering in industry is quick and accurate.

A mechanical bond is where surfaces are joined by adding another item such as screwing, bolting or sewing. Chemical bonding is when an adhesive chemical is added to join something such as glue.