As machining stresses are detrimental to the performance of a component, via the development of crazing in areas of localised stress, annealing or normalising will be recommended for the benefit of your acrylic component, with the procedure being carried out in-house. Other plastics can also benefit from annealing and this will be advised where appropriate.
Heat Treatment and Stress Relieving
Some materials, acrylic in particular, can benefit from heat treatment. The manufacture of cast acrylic causes internal stresses to be contained within the sheet, block or rod, which can affect the dimensional stability of a component. During machining, further stresses can be induced into the material. These can cause crazing in the presence of some solvents, particularly at areas of localised stress, which is detrimental to both the appearance and durability of the material. Heat treatment will relieve these stresses to ensure that the finished part will have a high resistance to solvent attack and have maximum dimensional stability.
Other materials can also benefit from stress relieving to retain dimensional stability, which may be carried out by interprocess relaxation or heat treatment. These materials include: