Is embalming necessary?
No, but the factors of time, health and possible legal regulations and religious beliefs might make embalming prior to cremation either appropriate or necessary. As a point of information, heart pacemakers or similar devices should be removed, because they may become dangerous when subjected to the extreme heat of the the cremation chamber.
Generally, if there is no viewing (closed casket) embalming is not necessary. However, embalming is necessary for viewing if an open casket is part of the funeral service. Also the factors of time, repatriating the deceased in the case of death occurring out of country, health, and religious beliefs might make embalming prior to cremation either appropriate or necessary.