Project Title

Plastic Injection Mold

Document Type


Date of Degree Completion

Spring 2018


Mechanical Engineering Technology

Committee Chair

Dr. Craig Johnson

Second Committee Member

Professor Roger Beardsley

Third Committee Member

Professor Charles Pringle


The engineering department at Central Washington University is equip with three different plastic injection presses. Two of which are not being used because of various reasons, one being a lack of quality molds. This project’s purpose was to design and fabricate a quality mold that could be used in one of the injection presses as a teaching aid. The design for this project is based off of existing molds that are currently being used in the plastic injection industry along with many analyses such as; calculating speeds and feeds for machining, calculating tolerances, material strength, and a material’s heat conduction properties. Fabrication commenced directly after the design was finished using manual, CNC machining processes, as well as some hand work. Testing of this mold was conducted in the Central Washington University’s engineering department. The mold was mounted in a Boy15 plastic injection press and tested for function and fitment. The injection press was then started and the mold was tested for its capability to produce quality plastic parts. The mold was able to produce many quality parts with minimal flash. Testing showed that the requirements for this project were met. The weight of the mold was 14lb out of an allowed 50lb, project cost came out to be just under $600 out of an allowed $1000, flash did not exceed 0.025”, the mold was able to produce at least 25 acceptable parts in succession, and it could be operated by one person.