Mold Operation Manual and Maintenance

General Overview

Applicable Equipment： Auto/Semi auto grommet/rivet setting machines, pneumatic/electric riveting machines.
Die Mold Composition：Medium / High carbon steel.
Core Function：High-frequency impact to achieve curling and secure fastening of the grommet /rivet onto the materials.

Align the exact center points of the upper and bottom mold, misalignment will cause eccentric impact, leading damage on the mold surfaces.

Change the corresponding riveting die mold whenever switching to a different grommet/rivet specification.

Ensure the die mold surface and feeding track are clear of remnants from previous operations before startup

Every Shift (8 Hours) Clear metal chips & Lubricate frequently.

Weekly (48 Hours) Check for work surface denting & Tighten mold holder bolts.

Monthly (200 Hours) Disassemble to clean & Check spring fatigue and hardened layer wear

Daily Maintenance (End of Each Shift)

Debris Cleaning：Use a pneumatic air duster to clear metal chips and dust from the die mold cavity and punch area.
Surface Lubrication：Apply a trace amount of specialized lubricant to the rolling parts of the mold.
Visual Inspection：Check the bottom mold curling groove for visible scratches or chipping.

Weekly Maintenance

Deep Tightening：Check and tighten the die mold holder positioning bolts to prevent die mold displacement caused by high-frequency machine vibration.
Alignment Calibration： Manually jog the machine to test the stroke depth and smooth entry of the upper into the bottom mold.

Monthly & Long-Term Maintenance

Disassembly Cleaning：Remove the mold parts and soak them in a cleaning solvent to remove carbon deposits and grease buildup.
Spring Replacement：Inspect the return springs of both die molds for fatigue or deformation. Replace proactively if necessary.

Expected Lifespan Indicators

Standard Lifespan：Under standard operation, heat-treated medium carbon steel die mold have an expected lifespan of 80,000 to 100,000 cycles for grommet mold and 130,000 to 150,000 cycles for rivet mold
Surface Hardened Layer：Carbon steel only relies on a thin hardened case layer (approx. 0.5–1mm deep). Once worn through to the soft core, the die deforms and scraps rapidly.
Refurbishment Cycle：Lightly polish the bottom mold groove every 10,000 to 20,000 cycles. Avoid excessive grinding to prevent wearing through the hardened layer.

Key Factors Affecting Lifespan

Hardware Material：Carbon steel die molds are only suitable for soft brass or aluminum grommet. Do not use stainless steel or hard iron grommets, which will cause immediate denting.
Eccentric abrasion：Excessive gap in the machine spindle causes lateral force on the punching mold, will reducing mold lifespan.
Pressure Settings：Excessive pressure at the bottom mold center (over-riveting) accelerates mold fatigue and causes cracking.

Defective Curling：Edge splitting or uneven curling of the eyelet that cannot be resolved by adjusting machine parameters.
Geometric Deformation：When the center pin of bottom mold became thinner, causing the internal diameter of the grommet deform.
Irreversible Damage： Visible damage (deformation) or serious cracking on the mold surface.

Symptom	Potential Cause	Remedy
Uneven or rough eyelet curling	Metal chips buildup or abrasion on the bottom mold	Clean with a soft cloth or perform light polishing
Piercing noise during riveting	Molds misalignment or extreme lack of lubrication	Re-calibrate the centerline and apply lubricant
Punch jammed/fails to recover	Broken return spring or internal debris obstruction	Disassemble the mold, replace the spring, and clear debris