Joining and Finishing Plastics Flashcards
What are some Bolts called?
Machine Screws - must have threat over the entire length
What must Nuts do?
Match the same thread as the bolt and they come in a variety of types
What is a Washer used for?
Under the nut to protect the plastic surface
What is a sprung washer?
Stop the nut from vibrating loose
What are Female Threads?
Sometimes cut into one piece of plastic and a machine screw then used to hold plastic components together
How are plastic threads made?
Usually injected moulded
What is Hot Melt Glue used for?
Quick modelling but not final products
What is Epoxy Resin?
Very versatile but expensive adhesive
Sticks most clean dry materials
Resin and hardener mixed together and sets chemically
What is the most common type of solvent cement?
Dichloromethane - dissolves the surface of hard plastics eg. acrylic
What are examples of products that can be self finished?
Injection moulded products
How are Injection Moulded plastics self finished?
The mould that cuts the product is highly polished or textured ensuring the same surface is transferred onto each product
How are cut edges of plastic filed?
Smooth file
Wet and dry paper wetted with water
How are hard plastics polished?
Using metal polish by hand with a cloth
Compound applied using a buffing wheel
What are the problems with polishing compounds?
Easy to overheat the edge of the plastic (by pressing too hard on buffing wheel)
Can permanently damage
What are Smart Materials?
React to outside stimuli and change their properties as a result
eg. become different shapes/colours
