BJY 98 × 35.58 mm Neck Ring

A neck ring works under conditions that punish soft metal. The clamping unit closes two steel halves around the preform thousands of times per shift, and each closure is an impact. Foshan Baijinyi (BJY) builds this 98*35.58mm insert from mold steel hardened to HRC 53 and finishes the forming face with a DLC diamond coating. The production experience of the Foshan workshop since 2011 demonstrates why this combination should be adopted.

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Features
Technical Indicators
Overall Dimension

A neck ring works under conditions that punish soft metal. The clamping unit closes two steel halves around the preform thousands of times per shift, and each closure is an impact. Foshan Baijinyi (BJY) builds this 98*35.58mm insert from mold steel hardened to HRC 53 and finishes the forming face with a DLC diamond coating. The production experience of the Foshan workshop since 2011 demonstrates why this combination should be adopted.
The Load the Neck Ring Carries
The insert holds the preform thread, the sealing face and the support ring while high-pressure air expands the body. It also takes the full closing force of the mold, applied directly to the small area of the split edges. High hardness at that edge is what keeps the two halves closing on a defined line instead of a worn one.
What Happens When Hardness Is Too Low
Steel below the required hardness peens over at the split corners. The corners round, the clamp contact becomes uneven, and molten resin finds the opening during the blow or injection stroke. The visible result is preform flash that leaves the plant with sharp edges around the neck. Threads also lose their thread form, so caps no longer run to torque, and leaks appear later on the filling line.
Hardening to HRC 53
BJY hardens every neck ring body to HRC 53, then applies a DLC diamond coating over the forming surface. The coated face carries a low friction coefficient, which lets polymer release without scuffing, and a hard surface that resists abrasive wear. Tests from running molds show the treatment extends total mold life by more than 10%, because the edges that define the seam stay where they were machined.
Supplied with Molds and Sold Individually
The neck ring ships as a standard part of a BJY mold set, and it is also available on its own. Individual supply exists for plants that must replace an insert which is already damaged, worn, or causing defective preforms. Each replacement is cut to the original coordinate datum and measured on a coordinate measuring machine before dispatch. It seats in the existing pocket without filing or shimming, so the seam closes correctly on the first cycle and the flash stops.