Exam Style Questions: The Use of Finishes Flashcards
Suggest one advantage, one disadvantage and one suitable application for each of the three print processes below (9 marks)
- Offset lithography
- Flexography
- Digital printing
Offset lithography:
Advantage - High quality, fast, cheap for high volume production, finishes
and spot colours can be easily integrated.
Disadvantage - Expensive set-up costs, longer lead time, limited ink types.
Application - Books, magazines, newspapers.
Flexography:
Advantage - High quality, cost effective for high volume production, prints
onto most surfaces, can print onto 3D surfaces e.g. cans.
Disadvantage - High set-up costs, set-up takes time which causes
downtime, output is less refined compared to offset
lithography.
Application: Packaging, flexible/3D forms
Digital printing:
Advantage - Low set-up cost, short lead time, versatile, customisable.
Disadvantage - Not cost-effective for high volume production, not as good
quality as offset and flexography, slow process compared to other
commercial methods.
Applications: Leaflets, brochures, posters, low-volume production.
Which one of the following print finishes is hardest to recycle? (1 mark)
- Encapsulation
- Foil blocking
- Varnishing
- Lamination
Encapsulation
Which one of the following best describes the method used to commercially print
onto plastic bags and drink cans? (1 mark)
- Ink jet printing
- Offset lithography
- Screen printing
- Flexography
Flexography
State three benefits of using lamination on papers and boards (3 marks)
- Enhance aesthetics
- Tear-proof
- Increase strength
- Add protection
- Protect ink
- Guard against moisture
- Create scratch resistant surface
- Create a wipe-clean finish
Explain why embossing and debossing might be described as a waste-free finishing process (2 marks)
Award 1 mark for a correct response and a further 1 mark for a relevant
explanation up to a maximum of 2 marks.
- No inks are required (1) so no excess ink/waste materials need to be
washed away (1). - No materials are added or removed during embossing/debossing (1) therefore
there is nothing extra to dispose of (1). - Dies used to create the embossing are made from steel (1) this can be recycled
easily (1).
A high-end catalogue is due to be printed and finished using offset lithography. Explain two ways in which costs of the print run could be reduced (4 marks)
Award 1 mark for each correct response and a further 1 mark for a relevant explanation up to a maximum of 4 marks.
- Reduce the number of colours required for the print (1), this reduces set-up costs and fewer printing plates are required (1).
- Remove all non-essential finishes (1), each process adds to time/materials required for each print (1).
- Use flexography (1), less expensive process but with a high-quality finish (1).
- Use a lower quality substrate (1), to reduce cost of materials (1).
Compare digital printing and screen printing as potential methods for printing
the greetings card (6 marks)
Screen printing:
- Simple shapes and forms on the motif would screen print well, no need for high definition print
- Screen printing would only require two printing screens (if working on a white coloured substrate), fewer screens means production time is reduced
- Screens would need to be prepared which would increase the lead time compared to digital printing
- Lead time on screen printing is relatively short as screen preparation is not a complex process, however, lead time on digital printing is even shorter
- Screen printing jigs can be used to align screens and speed up production, making the process more cost-effective
- Digital printing would produce prints more quickly
- This particular graphic has a high margin for error in terms of alignment (no two printed colours touch)
- Digital prints print all four colours in one operation so problems with registration/alignment are unlikely
- Screen printing is a more labour-intensive process
- Both methods are suitable for low volume production, such as seasonal goods
- Files for digital printing are very easy to edit
- Set-up costs for screen printing are relatively low as screen preparation is not complex and the screens and inks can used for multiple jobs, however, digital printing has extremely low/no set-up costs at all (other than initial purchase)
- If screen printing, the spot colour process would be best suited to this product as fewer prints would be required compared to a CMYK process
- Digital printing is limited to the CMYK/four colour printing process
- If the scale of production was increased, then neither screen printing nor digital printing would not be such a suitable process
Explain the process of overmoulding using two separate injection mouldings (5 marks)
Award 1 mark per relevant point up to a maximum of 5 marks.
The main thermoplastic body is moulded first (1) this is called the substrate (1).
The substrate is removed from the first mould when cooled (1) and placed into the second mould (1) where there are additional cavities for the overmoulding (1).
The TPE is heated and injected into the second mould creating the overmoulding (1).
Give two ways in which pigments can be used to enhance polymers (2 marks)
Add colour / aesthetic (1), provide a thermographic reaction aesthetic / function /
safety (1).
Provide a phosphorescent glow when charged with daylight aesthetic / function /
safety (1). Accept UV colour change as an alternative.
Acrylic spray paints can be used on some polymers.
Describe how to prepare an ABS moulding for spraying with acrylic paint (4 marks)
Award 1 mark per relevant point up to a maximum of 4 marks.
Clean and dry the surface (1), abrade to provide a key (1), clean again and ensure
all dust is removed (1), apply primer coat (1), allow primer to dry (1), apply paint in a smooth even coats (1), allow to cure/dry in-between coats (1)
Describe the process of joining two pieces of acrylic with a solvent cement (4 marks)
Award 1 mark per relevant point up to a maximum of 4 marks.
Acrylic cement / Tensol / liquid solvent cement is used (1) which are single part adhesives (1). Surfaces should be clean (1) solvent cement is applied and if necessary, the joint may need to be clamped (1) as the solvent evaporates (1). The solvent creates a permanent bond (1) by creating a chemical weld (1).
Give two stages in the production process when pigment can be added (2 marks)
Award 1 mark per relevant point up to a maximum of 2 marks.
Added to the polymer mix in the production of stock forms (1), added to neutral polymer granules in the hopper prior to moulding (1).
Name two reasons why a finish might be applied to wood (2 marks)
Award 1 mark for each correct answer up to a maximum of 2 marks.
- Prevent insect attack
- Prevent fungal attack
- Increase durability
- Increase resistance to heat
- Increase resistance to moisture
- Increase resistance to chemicals
- Improve/change aesthetics
Name one piece of personal protective equipment (PPE) you would recommend
while applying polyurethane varnish (1 mark)
- Face mask
- Gloves
- Eye protection
- Apron
- Respirator (if high VOCs)
Wax finishes nourish and protect wood. Give a further two advantageous
characteristics of a waxed wood finish (2 marks)
Award 1 mark for each correct answer up to a maximum of 2 marks.
- Easy to apply
- Natural finish/enhances natural beauty of the wood
- Easy to remove
- Available clear or with tinted finish
