Calendering Manufacture Process

The main material used in PVC, but ABS cellulose acetate. After all the material have been mixed, its is transported the first of a 'two roll mill' where its is then banded onto one roll. The material passes through a series of roller usually decreasing thickness as the process continues. The rollers have a surface area between 160 and 220 degrees this is required in the production of PVC. The distance between the rollers controls sheet thickness. Machines usually have three pairs of nip roller points this enables the material to gradually be reduced in thickness.

The film is then tranfered to a 'post calender chain' , a series of cooler rollers where the temperature of each roller decreases in temperature by 2-5 degrees celcius.

The film is finally rolled onto rolls, the entire process is shown below.

Flat Pack Chair: Inspired By Arne Jacobsen's Organic Design

Materials Knowledge List

Moulding

INJECTION MOULDING

Heated granules injected by hydraulics. NO WASTE. Used for detailed plastic goods.

COMPRESSION MOULDING



The stages are as follows:

1. The mould is heated.
2. A 'slug' or piece of the selected plastic is placed into the mould and warms up.
3. The hydraulic press begins to move down when the plastic has reached the correct temperature..
4. As the upper and lower mould meet, the plastic is compressed into the shape of the mould.
5. The upper mould moves upwards and the plastic piece (in this case a tray) is removed.

Rotational Moulding

During the heating stage, the mould slowly rotates in two planes (bi-axial rotation). Heat transfer causes the plastic charge inside the mould to melt and uniformly coat the interior of the mould.

During the second stage, the mould moves to the cooling station where it is cooled by air and/or water spray.
In the final load/unload stage, the part is removed from the mould and a new charge of material is loaded into the mould.



Polymers/Plastics

POLYMERS = plastics

Thermoplastics

Can be shaped and remoulded, due to no links between Polymer Chains.
Available to recycle.

Thermosetting

Very hard to get back to original form, due to strong Polymer links.
Commonly found in Resins, Powder forms for Compression Moulding.


Polymers

• Good strengh to weight ratio
• Generally good resistance to atmospheric and chemical erosion.
• Low melting point
• Lightweight
• Wide range colours / Pigments added / transparency**

THERMO POLYMERS                                               

• ABS
• CA
• POLYAMIDE/NYLON/PA
• PMMA-ACRYLIC
• PP
• POLYSTYRENE
• LDPE
• HDPE
• uPVC
• PVC
• PET

Hard Hat: ABS, Hard, Lightweight, easily shaped,durable, hard wearing.

Water Bottle: PET, Flexible, easily shaped, lightweight.

Bucket: HDPE, Good tensile strengh, Lightweight.

Storage Tubs: PP, Easily shaped, Transparency.

Lights: PMMA/ Acrylic, can be transparent.

PVC: Very flexible.

THERMO SETTING POLYMERS

Epoxy Resins: Surface coatings, Encapsulation of electronic components,Adhesives.

Melamine Formaldehyde: Tableware, Decorative Laminates.

Polyester Resins: Castings used in GRP.???

Urea Formaldehyde: Electrical fittings, Adhesives.



Assignment 1

I purchased a Dolce and Gabbana belt last Christmas for £85.00. I purchased the belt due to its aesthetics and the attractive look of the belt. Due to the Italian brand 'D&G' the belt is extremely over priced for its functionality. Dolce and Gabbana is a recognised brand in fashion, creating new and iconic pieces of clothing and shoe wear. The material is high quality leather from Milan,Italy, the top grade leather adds price to the belt also. After only a few hours of purchasing the belt, I had realised the mistake i had made. The overall quality of the belt was very similar to less expensive belts. The function of the belt, which is very simple didn't match the price of the belt. For this reason I wish I had never purchased the product and returned it to the store the following day. Although Dolce and Gabbana are one of favourite brands the purchase was not necessary, due to the lack of function of the product.

Similar belts on the market include a belt from 'Primark',at a much cheaper price than the 'Dolce and Gabbana belt. Although there are many differences. The quality of the material from D&G is exceptional, quality leather compared to synthetic material used on many rimark belts. The buckle on the top priced belt has a very attractive design, which had been produced to a quality standard. The Primark buckle was poor made and designed with very little effort or imagination. The Primark belt would mostly likely break or become tarnished very quickly in contrast the D&G would last a very long time due to the quality leather. In conclusion there lies the reaon for the greater price of the D&G belt, however quality can easily be overlooked depending on the price of thus product.