Jigs and Fixtures to aid repetition

Jigs, Fixtures & Templates These are essential to gain consistency when making more than one product. If the exam has a question on batch production, these devices must be mentioned.

Jigs and Fixtures

Quantity Production Dependent on demand, products are made in a range of quantities from large-scale mass production (screws, light bulbs, etc.) to a one- off product (bespoke furniture). At each level there are both advantages and disadvantages. In manufacturing, time is often the most expensive commodity, so the ability to speed up production has an advantage.

Jigs and templates are commonly used to help increase accuracy, speed of operation and reduce the need for highly skilled workers.

The success of a jig Always locate the material against a reference (datum) edge. Avoid waste material getting trapped. Secure the work quickly and easily (hand, toggle clamp or cam). Be made from a suitable material to avoid wear which is likely to lead to inaccuracy.

This question is about quality control. You are advised to spend about 10 minutes on this question. Study the metal plate shown below. This metal plate is to be made in a school workshop. Produce a labelled drawing of a simple drilling jig that will allow 100 similar metal plates to be drilled. Your design must include: The holes to drill through An x-direction limiter A y-direction limiter A clamping/locking device Be easy to use Design a jig for the question below. Remember the jig should aid the production of the part without measuring out each time. It must locate onto the component and prevent it moving out of place. 6 guide holes X direction limiter Y direction limiter Locking device Ease of use 5 marks

Benefits of Jigs and Fixtures Accuracy: The level of accuracy is improved as human error is limited. Consistency: The level of consistency is improved as all the products will be identical. Speed: The time taken to produce a product is reduced as there is no requirement for marking out. Cost: The cost of producing products is reduced as the use of jigs, moulds and templates means less labour is required. Initial set up cost is high.

Making multiple products The traditional method

Stage 1 (4 marks) Marking out – traditional Sufficient detail for most of the design to be marked out by a third party, in quantity, using a template. Most tools and equipment given. Plastic: Template used. Pen to mark out Tessellate marking out Sketch this process Metal: Template used. Scriber to mark out Tessellate marking out Sketch this process Wooden: Templates x2 Pencil to mark out Tessellate marking out- sketch this process

Stage 2 (4 marks) Cutting and shaping (traditional) Sufficient detail for some of the design to be cut and shaped by a third party as a one off. Most tools and equipment given Sufficient detail for most of the design to be cut and shaped by a third party, in quantity, using jigs/templates. Most tools and equipment given. Plastic: Scroll saw Files Jig Metal: Tin snips Junior hacksaw Jig Files Wooden: Tenon saw Bench hook Scroll saw Jig Draw at least one diagram Power tools – jigsaw/band saw

Stage 3 (4 marks) Bending/joining - traditional Sufficient detail for most of the design to be bent/joined, in quantity, by a third party with use of jigs/formers. Most tools and equipment given. Plastic: Strip heater Former to bend around – draw the former and plastic folding around it Metal: Folding bars - jig Or former to bend around – draw the former and metal folding Wooden: Drilling jig and pillar drill Dowel points Glue dowels into holes Gluing jig to hold parts together – draw dowels as exploded diagram Draw at least one diagram

Stage 4 (2 marks) Applying the surface finish (traditional) Sufficient detail for the design to be finished by a third party. Most tools and equipment given. Look for the following details: Material preparation Use of a brush/aerosol/rag Application of varnish/paint Plastic: File and wet and dry edges Polishing wheel Metal: File and wet and dry edges De-grease with rag Aerosol paint to be applied – primer first, allow to dry then top coats. Wooden: Sand paper Make sure it is dust free Varnish and brush Allow to dry Gently rub down with wire wool Apply top coat Draw at least one diagram

Stage 5 (2 marks) Producing the text (traditional) Sufficient detail for the logo to be applied by a third party, tools and equipment given Look for the following details: Use stencil/template Application of varnish/paint Plastic: Use stencil Aerosol spray paint over stencil Allow to dry Metal: Use stencil Aerosol spray paint over stencil Allow to dry Wooden: Use stencil Aerosol spray paint over stencil Allow to dry Draw at least one diagram

6 Your drinks mat holder is made from aluminium but it could also have been made from acrylic. Use a template to draw around so that each shape is identical. Use a powered tool such as a band saw to cut them out as this will be more accurate than by hand with a coping saw. Double sided sticky tape would hold more than one together when cutting. Check as you cut. Use a jig or former to bend the acrylic to the same angle using a strip heater. The jig or former should be the correct shape and be easy to place the acrylic onto. It should not be affected by the heat of the acrylic.

If checks are made you will have a higher quality product which helps make each product consistent. The checks will make sure each product meets the required standards set out by the manufacturer. There will be less faults on the product which makes them more popular for the customer and they will be more cost effective in the end to the manufacturer.

Give two reasons why acrylic is not considered to be an environmentally friendly material. Explain each reason. Reason 1: (1 mark) Explanation: (2 marks) Reason 2: (1 mark) Explanation: (2 marks ) 7

8 a Your drinks mats must be made to a certain size to fit within the holder. If they are too large or too small the product will either not look attractive, or it will not function. Explain the importance of tolerance when manufacturing components. ……………………………………………………………………………………………………………………………….. Explain the importance of quality control to the consumer. …………………………………………………………………………………………………………………… 8 b 4 marks Quality control gives the consumer a better quality product It has undergone numerous checks throughout its manufacture Quality control gives the consumer a more reliable product There is less chance of a part of the product failing as each component is independently checked. Maintenance possible because all components are manufactured to a set tolerance facilitating interchangeability 4 marks Tolerance: The amount of error that can be allowed and is often given as +/- mm. It is more important in some products than others. Very difficult to make a component exactly correct. Easier to make a component within tolerances. This is the maximum and minimum sizes a component can be. Manufacturer knows that if a product is within tolerances then it will work.

8a Award one mark each for details relating to the importance of tolerance when manufacturing components. Very difficult to make a component exactly correct Easier to make a component within tolerances This is the maximum and minimum sizes a component can be Manufacturer knows that if a product is within tolerances then it will work. (4 x 1 mark) 8b Award one mark each for the details relating to the importance of quality control to the consumer or two marks each for an expanded detail: Quality control gives the consumer to have a better quality product It has undergone numerous checks throughout its manufacture Quality control gives the consumer a more reliable product There is less chance of a part of the product failing as each component is independently checked. Maintenance possible because all components are manufactured to a set tolerance facilitating interchangeability (4 x 1 mark) 12 marks

Making multiple products CAD/CAM method

Stage 1 Marking out (CAD) (4 marks) Marking out CAD Sufficient detail for the design to be drawn by CAD by a third party. Most tools and equipment given. Look for details relating to: Computer hardware – PC, mouse, keyboard Software – 2D Design Net on screen – draw this out! Use of different coloured lines Power settings 2010 images E.g. red engrave, blue cut Acrylic requires 100% Slow speed 0.4mm/s for cut 4mm/s for engrave

Stage 2 (4 marks) Cutting and shaping CAM Sufficient detail for the design to be manufactured by CAM. Most tools and equipment given. Look for details relating to: Make sure laser and extractor is turned on Send to machine via File>Print Lift lid and place material inside on bed – no need to clamp down Make sure bed height is set correctly for material thickness Double check settings are correct Close the lid or the machine will not run Press to start cut/engrave

Stage 3 (4 marks) Bending/joining - traditional Sufficient detail for most of the design to be bent/joined, in quantity, by a third party with use of jigs/formers. Most tools and equipment given. Plastic: Strip heater Former to bend around – draw the former and plastic folding around it

Stage 4 (2 marks) Applying the surface finish (CAM) Reference to the fact that a laser cut stand would not need finishing as the laser produces a good quality finish. or Reference to improving the quality of laser cut edges by using wet and dry paper and polishing wheel/mop.

Stage 5 (2 marks) Producing the text (CAD/CAM) Reference to the fact that the logo would be etched in by the laser Look for the following details: The logo being produced on a graphics software package (2D design) The logo being etched by the laser cutter at time of cutting or The logo being produce by the vinyl cutter and then stuck on