Method of manufacturing an orbiting scroll in a scroll fluid machine

A method of manufacturing an orbiting scroll in a scroll fluid machine, the method comprising the steps of:

• providing an orbiting scroll material;
• forming a first inner reference bore near a center and a first outer reference bore near an outer circumference axially in the orbiting scroll material at high precision on size and location;
• forming an orbiting wrap and a plurality of cooling fins on the orbiting scroll material;
• applying surface treatment on the orbiting scroll material;
• providing a bearing plate material;
• forming a second inner reference bore near a center and a second outer reference bore near an outer circumference at high precision axially in the bearing plate material at positions corresponding to the first inner reference bore and the first outer reference bore of the orbiting scroll material;
• aligning the first inner reference bore with the second inner reference bore and first outer reference bores with the second outer reference bore without surface treatment to the bearing plate material;
• and
• inserting a first dowel pin into the first and second inner reference and a second dowel pin into the second inner reference bore and the second outer reference bores to combine the orbiting plate material with the bearing plate material to obtain the finished orbiting scroll.