Direct Tool Production (DTP) by Laminated Object Manufacturing (LOM) technique is being widely investigated to replace conventional tool production techniques. The advantages of LOM techniques lie in their reduction in both manufacturing cost and the lead time. Given this scope for cost reduction, industries are concentrating on the DTP to increase their flexibility and reduce lead times. The major problem with the LOM techniques is the ‘staircase’ effect that occurs due to the discrete height of the laminates. Various techniques are being investigated to remove the steps such as high speed machining, electric-discharge machining (EDM) and slant cutting. This paper presents the results of experimental investigations to remove or overcome the “staircase” effect using slant cutting, laser machining or blown powder cladding techniques.
The slant cutting and cladding processes were investigated using CO2 laser. The effect of different cutting gases and cutting gas pressures has been investigated including the use of oxygen, air and nitrogen. A high pressure Laval nozzle was used for air and nitrogen assist gas cutting. On the other hand, the blown powder technique was investigated to fill the steps on laminated parts. An appropriate sized clad track is deposited in the bottom of each step to improve the overall smoothness of the part
An Nd:YAG laser (LUMONICS JK704TR) was used in the laser machining of the laminated steps. The influences of laser parameters and traverse speed were investigated.