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Dynamic feed rate in multiple independent spindles cnc milling machine for orthotic insole manufacturing
Author(s)
Date Issued
December 1, 2019
Type
Article
Abstract
Diabetic foot ulceration can be prevented in case of the high plantar pressure being reduced and transmitted from ultimate stress point to the total area of plantar tissues. Custom-Made Insole (CMI) is one of the practical techniques to reduce ultimate stress on the patient’s foot. By employing the CAD/CAM technology, CMI for diabetic patients can be made fast and cost effective in comparison to the conventional method. In this research, there were two major improvements which made the CMI manufacture even faster and cheaper. First, a foot sole surface impression machine was developed to be compatible with the CMI configuration. The reusable foot sole impression machine can replace the traditional dispensable impression foam. An experiment was carried out to verify that pressure distribution on the impression surface was effective and comparable to the conventional method. The second improvement was the implementation of multiple independent spindles CNC system on the CMI cutting process. The configuration of multiple cutting tools and design cutting paths were investigated. In addition, the optimum cutting parameters were established using cutting force criteria. The relationship between cutting force and axial depth of cut was used to assign the feed rate. Because the feed rate which relates to the Z-direction can be varied among all spindles, two different techniques, fixed and dynamic feeds, were applied and compared. On average, the fixed feed technique can cut a pair of insole within 32 minutes, while dynamic feed can produce within 29 minutes. Overall both foot sole surface impression machine and multiple independent spindles CNC milling machine can cut down the production time to only 60% of the time used in typical CAD/CAM system, and 20.8% of the time used in conventional method.
Citation
International Journal of Innovative Computing Information and Control, 15(6), 2149-2163, 2019