Exam Style Questions: The Use of Finishes Flashcards

1
Q

Suggest one advantage, one disadvantage and one suitable application for each of the three print processes below (9 marks)

  • Offset lithography
  • Flexography
  • Digital printing
A

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.

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2
Q

Which one of the following print finishes is hardest to recycle? (1 mark)

  • Encapsulation
  • Foil blocking
  • Varnishing
  • Lamination
A

Encapsulation

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3
Q

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
A

Flexography

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4
Q

State three benefits of using lamination on papers and boards (3 marks)

A
  • Enhance aesthetics
  • Tear-proof
  • Increase strength
  • Add protection
  • Protect ink
  • Guard against moisture
  • Create scratch resistant surface
  • Create a wipe-clean finish
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5
Q
Explain why embossing and debossing might be described as a waste-free 
finishing process (2 marks)
A

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).
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6
Q

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)

A

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).
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7
Q

Compare digital printing and screen printing as potential methods for printing
the greetings card (6 marks)

A

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
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8
Q

Explain the process of overmoulding using two separate injection mouldings (5 marks)

A

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).

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9
Q

Give two ways in which pigments can be used to enhance polymers (2 marks)

A

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.

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10
Q

Acrylic spray paints can be used on some polymers.

Describe how to prepare an ABS moulding for spraying with acrylic paint (4 marks)

A

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)

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11
Q

Describe the process of joining two pieces of acrylic with a solvent cement (4 marks)

A

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).

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12
Q

Give two stages in the production process when pigment can be added (2 marks)

A

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).

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13
Q

Name two reasons why a finish might be applied to wood (2 marks)

A

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
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14
Q

Name one piece of personal protective equipment (PPE) you would recommend
while applying polyurethane varnish (1 mark)

A
  • Face mask
  • Gloves
  • Eye protection
  • Apron
  • Respirator (if high VOCs)
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15
Q

Wax finishes nourish and protect wood. Give a further two advantageous
characteristics of a waxed wood finish (2 marks)

A

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
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16
Q

Pressure treated timber is treated professionally. Give the two types of
pressure that timber is subjected to during this process (2 marks)

A
  • A vacuum/air pressure

- Hydraulic pressure

17
Q

A copper-based chemical solution is used for pressure treatment. Explain how
this protects the wood (2 marks)

A

Award 1 mark for a correct answer and a further 1 mark for a relevant explanation.

Copper has anti-microbial properties (1) which prevents insects/fungi
from feeding on the wood (1).

18
Q

Give one common application of pressure treated timber (1 mark)

A
  • Fencing
  • Decking
  • Playgrounds/climbing frames
  • Construction
  • Landscaping
19
Q

Evaluate the advantages and disadvantages of using polyurethane varnish
to finish woods (6 marks)

A

Advantages:
- Extremely hard wearing / scratch resistant
- High level of chemical resistance
- Creates a waterproof/water resistant surface
- Excellent protection against heat damage
- Lustrous finish – available in matt, satin or gloss finish
- Gives a durable coating to paint/stain finishes
- Available as a clear or tinted finish for different aesthetic looks
- Available as a water-based or solvent-based finish which gives consumers
choice

Disadvantages:

- Can yellow over time if exposed to UV light
- High level of VOCs – danger to health and environment
- Requires chemicals for clean up
- May make wood look less authentic
- Fairly long drying time
20
Q

Explain the process of powder coating (5 marks)

A

Award 1 mark per relevant point up to a maximum of 5 marks.

The product cleaned and degreased (1); it is then electrostatically charged (1); powdered paint sprayed through an air gun (1); the charge provides a strong attraction between powder and the product attaching it to the product (1); the product is then baked in an oven (1); the heat melts and bonds the powder onto the product (1).

21
Q

Give two ways in which paint can be used to enhance metals (2 marks)

A
  • Add colour/aesthetic

- Provide a barrier against corrosion/protection

22
Q

Both cellulose and acrylic paints can be used on metals.

Describe how to professionally finish sheet metal using sprayed paint (4 marks)

A

Award 1 mark per relevant point up to a maximum of 4 marks.

Clean and degrease the metal surface (1), spray using professional spray gun equipment (1); in a heated (1); and well ventilated area (1); apply primer coat (1); apply undercoat (1); apply paint in a smooth even coat (1); allow to cure/dry in heated area for up to 24 hours (if appropriate) (1).

23
Q

Describe the process of electroplating metals (4 marks)

A

Award 1 mark per relevant point up to a maximum of 4 marks.

  • Electroplating uses a metal to coat a (cheaper) base metal (1). The object and
    the coating metal are placed in an electrolyte solution of the coating metal (1).
  • The object to be plated acts as the negative electrode (cathode) (1), with the
    coating metal acting as the positive electrode (anode) (1), an electric current is
    passed through the solution causing the coating metal to oxidise (1) and dissolve
    in the solution (1), thus transferring the dissolved metal ions to be reduced at the surface of the object to be plated (cathode) (1).
24
Q

Give two reasons why preservatives are used in moulds and dies (2 marks)

A

Award 1 mark per relevant point up to a maximum of 2 marks.

To provide temporary or long-term protection to the metal surface of the mould or die (1), to provide a consistently smooth surface (1), to prevent atmospheric corrosion (1), to prevent condensation build up (1).

25
Q

Evaluate the use of galvanizing steel by hot dipping versus galvanising steel by electroplating (6 marks)

A

Hot dip galvanizing:
- Thicker coating than electroplating provides, resulting in better corrosion
resistance especially for outdoor use
- Long maintenance-free service life as a result of the thick coating
- Lower cost for multiple items than electroplating
- Items such as bolts and component parts must be manufactured taking into
account the additional thickness the zinc coating will give. This could result in
parts not fitting together as planned and additional time and expense in
manufacture
- Easier process to use for large scale items such as trunking and piping than
electroplating due to the size and scale of hot dip baths

Galvanizing using electroplating:
- Thinner coating than hot dip process making it less suitable for long term
outdoor use
- Better surface brightness than hot dip galvanizing produces
- Uniform colour produced unlike hot dip galvanizing makes it the more
aesthetically pleasing option
- Less consideration needs to be given to tolerances of components prior to
galvanizing than hot dip galvanizing as top coat is much thinner