When your component needs to be of exceptional visual appearance, have high resistance to solvent attack or have good dimensional stability, it will benefit from heat treatment.
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.