Design For Manufacturing Maintenance, Repair & Disposal Flashcards
Ease of manufacture
What 2 adv does efficient manufacture provide
Name 4 ways this can be done
Tip: modular, obvs, hard-circuits, layout
Efficient manufacture obvs vital to reduce costs & maximise p. quality. This is done by:
Use modular designs with easy to monitor sub systems
Standardized parts
HARD -Use wave or reflow methods of making circuits rather than soldering
Ensure optimal layout of manufacturing systems by using simulation software
Reducing number of manufacturing processes
AO
What is a major thing to consider when reducing the number of processes
How can this be done, 7
Tips: redistribution, self finish, joining, ribs, integral snap fittings, buy parts, adhesives
Less process = obvs easier, but need to ensure it doesn’t make p. less sustainable or repairable
This is done by:
- Good point -Use single redistribution process eg injection, rather than multiple addition or wastage
- Use self finishing materials
- Reduce joining processes by using integral fixings
- Use ribs and webs to make light but strong casting and moulding
- Use integral snap fittings, posts for self tapping screws and texture in moulds
- Buy parts from specialist rather than in house
- Use adhesives rather than metal fasteners
Choice of material
What helps with separation of recycling
How can products be more easily disassembled/separated
Tip: cradle, standard, ELV, SMA, snap fittings
Material affects use, care, disposal
Labelling of materials to help separation for recycling achieved by use of standardised system of codes.
‘cradle to cradle’ approach keeps materials in products separate
Standard screws such as Pozidriv that anyone can remove
Adhere to ELV End of Life Vehicle legislations for car dissassembly
Use smart materials for automatic ‘active disassembly’ of p. eg phones
Use easily released polymer snap fittings eg polymer clip based fastenings used in hoovers
6 R’s
Sustainability def
Sustainability is the management of the resources to minimise depletion and pollution
Recycle - Recovering parts and materials to be used again when p. reach end of useful life
Reduce - Minimise wastage by using less material, packaging
Refuse - Avoiding designs which are harmful to env or difficult to recycle
Repair - Design p. that can be repaired rather than thrown out
Rethink - Consider
Reuse -
IBZ:
Reducing thickness
What adv does this give but what must also be considered
Ribs
how can it be made
Webbing
how can it be made
Whats the difference between them
Integral fittings
What are snap fittings what are adv of them where are they used
Type of snap fittings
Cantilever, annular, torsion, U-shaped:
Internal mould screw posts:
Pre-made components:
Standard patterns:
Textured moulds:
Self finishing:
Reducing weight and thickness = save resources and costs
This must be done whilst maintaining the strength of p.
thickness can be reduced if ribs or webs used. This increases strength + rigidity
Ribs:
Ribs can be used with a number of materials and may be created in different ways
- could be integrated into a model by pressing, forming , folding or weaving
- Sometimes ribs of stronger material may be added to thin sheet to increase strength
Webbing:
Reduces material thickness by using integrated webs to strengthen and support structure
- In plastic p. done by injection, in metals, done by casting
- Could also be fabricated or moulded by lay up
The difference between them - rib is around corner, web is along whole surface.
Integrated fixings:
remove need for adhesives/fixings = reduces no. parts needed = less processes so saves time and money and increases recyclability
Snap fittings parts aka push fit, often moulded and have integral clips or ridges that ‘snap’ into place
Snap fittings are usually detachable
Enables rapid disassembly and assembly
eg remote battery opening, pen lids, plumbing fittings
Types of snap fittings - 4 types
Cantilever, annular, torsion, U-shaped:
-Cantilever - Basically a buckle like bicycle helmet
The tang goes into the cantilever
-Annular snap fittings - multi use and use in products like pen lids, cups and bottle caps
more elastic part pushed into more rigid part
ridge on male part mates with gully on female part
annular snap fittings usually circular however BALL and Socket joint is also annular.
-Torsion and snap fitting - more complex less common, better suited to applications where regular opening and closing is required. They have a pivot and hinge, allows them to open when pressure exerted. Shear force is exerted to open the fixing.
- U shaped snap fitting - Its a variation of the cantilever, more commonly used in battery housing. the U form increases length and creates spring allowing greater deflection. Used where materials are less flexible.
Internal mould screw posts:
Where snap fittings aren’t appropriate. Used if p. requires occasional assembly/disassembly. May use internally moulded screw post.
Used in electrical and electronic p. and enable easier disassembly. Easy and economical to make in 1 mould.
Pre-made components:
Some manufactures buy standard components from external suppliers to use. Allows them to reduce costs cuz no manufacturing specialist parts.
Standard patterns:
Patterns and templates in standard sizes used when designing and making many p. including clothes. Body forms used to create patterns in different fits and sizes eg M X XL XLL etc.
Textured moulds:
Can be functional and aesthetic. Improve grip, create lettering and logos and simulating other materials eg leather. Using a mould surface to achieve textured moulding is another way of increasing efficiency. The finish is integrated into the moulding or casting = removes need to finish.
Self finishing:
Using this can reduce no. processes so reduce cost. enhances aesthetics, makes it safe, protects material.
IBZ
The need for ease of disassembly:
Good - The need for ease of disassembly:
Easier analysis of p. research
Easier maintenance, repair, reuse, recycling
Increase in value of end of life p.
Reduction of need for specialist breaking facilities
less parts going to landfill
