HAIDIAN DISTRICT, China - s4story -- DMNC recorded a Ra 0.3 finish on an H13 zipper mold and a uniform VDI18 surface finish on a rubber watch-strap mold in two ADI300 machining trials. The results illustrate how a CNC spark erosion machine can meet different mold surface targets through sample-specific electrodes and machining conditions, with processing times and inspection findings recorded in both reports.

Zipper Mold Trial Meets Surface Requirement
DMNC machined an H13 zipper mold using two copper electrodes, with one assigned to roughing and one to finishing. The workpiece was fastened on a magnetic plate and machined while immersed in oil without flushing.

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The report records a final surface roughness of Ra 0.3, meeting the customer's stated requirement. Total machining time was reported as 1 hour and 21 minutes. The process summary lists 5 minutes and 38 seconds for roughing, 15 minutes and 13 seconds to reach Ra 0.8, and a further hour for the final transition to the reported mirror finish.

Watch-Strap Mold Achieves Uniform VDI18 Finish
The second trial focused on a rubber watch-strap mold requiring a VDI18 surface finish. DMNC used one copper electrode with a reported spark gap allowance of 0.1 mm per side. The setup also used a magnetic plate and oil immersion without flushing.

Inspection found a uniform machined surface finish that met the VDI18 requirement. According to the report, machining was completed with one electrode in 3 hours and 35 minutes. This trial illustrates a different finishing objective from the zipper mold, with surface finish uniformity serving as the reported acceptance result.

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Documented Trials Support Machine Evaluation
Both reports identify the equipment as an ADI300 CNC die sinker. Each records the machining setup and inspection outcome, allowing the surface requirement to be considered alongside electrode use and processing time. The results apply to the individual samples and recorded conditions.

For manufacturers reviewing CNC die sinking, these cases offer a practical reference for defining a trial. Workpiece geometry, material, electrode design and finishing requirements should guide the test plan; the recorded cycle times should be evaluated in that context.

Manufacturers considering EDM for zipper, watch-strap or other molds can contact DMNC with drawings, workpiece materials and surface targets to discuss a relevant sample test. A documented trial can help establish whether the proposed process meets the requirements of a particular mold before a broader production decision.