Operating Rules for Mold Fitters

1. General Provisions

1.1 Purpose

Mold fitters are the core trade in mold manufacturing and maintenance, responsible for mold assembly, debugging, repair, and maintenance. These operating rules are formulated to standardize the operating behavior of mold fitters, ensure personal safety, equipment safety, and mold quality.

1.2 Scope of Application

These rules apply to fitters engaged in mold assembly, debugging, repair, and maintenance in mold manufacturing enterprises.

1.3 Basic Requirements

• Mold fitters must undergo professional training and hold valid certificates
• Familiar with mold structures, assembly processes, and repair techniques
• Master the correct use of various fitter tools, measuring instruments, and equipment
• Strictly comply with safety operating procedures and process discipline

2. Safety Operating Rules

2.1 Personal Protection

• Must wear: Work clothes, safety shoes, protective glasses
• Prohibited: Slippers, sandals, loose clothing, jewelry
• Long hair must: Be tucked into a work cap
• When operating rotating equipment: Gloves are strictly prohibited
• When using power tools: Protective glasses must be worn

2.2 Equipment Safety

(1) Lifting Equipment

• Inspect wire ropes and hooks for integrity before using cranes or hoists
• Must use dedicated lifting rings when hoisting molds; wire or rope substitutes are strictly prohibited
• Standing under molds during lifting is strictly prohibited
• Lifting height not exceeding 0.5 m, move slowly

(2) Power Tools

• Check power cords and plugs for integrity before use
• Grinders and angle grinders must be equipped with guards
• Cut off power before replacing grinding wheels or drill bits
• Overspeed use of grinding wheels is strictly prohibited

(3) Hand Tools

• Hammer handles must be secure; loose hammers are strictly prohibited
• Chisel and punch tops must be free of burrs
• Wrench sizes must match bolts; extending with pipes is strictly prohibited
• Files must be fitted with wooden handles

2.3 Work Environment Safety

• Workbenches must be stable; workpieces must be clamped securely
• Keep floors clean; clean oil stains promptly
• Keep passages clear; place materials neatly
• Keep flammable materials away from fire sources
• Fire extinguishing equipment placed at designated locations, inspected regularly

2.4 Safety Operation Prohibitions

• Strictly prohibited: Operating after drinking alcohol
• Strictly prohibited: Operating while fatigued
• Strictly prohibited: Violating operating procedures
• Strictly prohibited: Removing safety guards without authorization
• Strictly prohibited: Performing maintenance while equipment is running
• Strictly prohibited: Removing chips directly by hand

3. Pre-Operation Preparation Rules

3.1 Drawings and Process Document Preparation

• Carefully read mold assembly drawings, part drawings, and technical requirements
• Familiar with assembly process specifications and assembly sequence
• Clarify critical dimensions, fit precision, and technical requirements
• Check parts list to confirm all parts are complete

3.2 Parts Inspection

3.3 Tool and Measuring Instrument Preparation

Common Tools:

• Copper rod, nylon hammer, iron hammer
• Hex wrenches, torque wrench
• Clamps, screwdrivers, pliers
• Oilstone, grinding paste, sandpaper

Common Measuring Instruments:

• Micrometer, vernier caliper
• Feeler gauge, red lead, dial indicator
• Level, square
• CMM (Coordinate Measuring Machine)

3.4 Parts Cleaning

• All parts must be thoroughly cleaned before assembly
• Remove burrs, oil, and chips
• Cavity and core surfaces cleaned with ultrasonic cleaning
• Cooling channels undergo water flow testing to check for blockages

3.5 Assembly Site Preparation

• Clean the assembly site and keep it tidy
• Prepare assembly platform, ensure stability
• Prepare parts storage racks, categorize and place
• Prepare lighting equipment, ensure adequate light

4. Assembly Operating Rules

4.1 Assembly Sequence Principles

• Bottom before top: Install bottom plate first, then moving/fixed mold bases
• Inside before outside: Install cavity/core first, then slides and lifters
• Main before auxiliary: Install main mechanisms first, then auxiliary mechanisms
• Static before dynamic: Install fixed parts first, then moving parts

4.2 Mold Base Assembly Rules

• Use the datum corner as reference for sequential assembly
• Use diagonal alternating tightening to prevent plate deformation
• Re-check parallelism after tightening; adjust with shims if necessary
• Apply molybdenum disulfide lubricant before pressing guide pins
• Guide pin perpendicularity error ≤0.01 mm/100 mm

4.3 Cavity and Core Assembly Rules

• Use red lead to check fit surface contact ratio; require ≥80%
• Use guide pins for positioning during insert pressing to prevent tilting
• Check fit clearance with feeler gauge after pressing; require ≤0.01 mm
• Cavity-core alignment error ≤0.02 mm

4.4 Slide and Lifter Assembly Rules

• Slide-to-guide rail clearance controlled at 0.02–0.05 mm
• Slide bottom surface contact ratio with mold base ≥80%
• Lifter angle error ≤0.01 mm
• Lifter return springs pre-compressed 10%–15%
• Slide-to-cavity sealing surface contact ratio ≥90%

4.5 Ejection System Assembly Rules

• Ejector pin-to-hole clearance 0.01–0.03 mm
• Ejector pin lengths consistent, error ≤0.02 mm
• Ejector pin end faces flush with cavity surface, error ≤0.02 mm
• Ejector plate-to-guide pin clearance 0.02–0.04 mm
• Ejection stroke precisely controlled with stop blocks

4.6 Hot Runner System Assembly Rules

• Add insulation pads between hot runner manifold and cavity plate
• Nozzle-to-sprue bushing alignment error ≤0.02 mm
• Tighten manifold bolts with torque wrench in diagonal sequence
• Nozzle-to-cavity sealing surface contact ratio ≥90%
• Perform water flow test and heating test after assembly

4.7 Cooling System Assembly Rules

• Cooling channels undergo water flow test to check for leaks
• Water pipe fittings wrapped with PTFE tape or coated with sealant
• Cooling channels undergo flow rate testing to ensure uniform flow
• Cooling channels undergo 0.5 MPa water pressure test, held for 30 minutes without leakage

4.8 Assembly Precautions

• Never strike mold parts directly with an iron hammer
• Keep parts clean during assembly
• Apply grease to all moving parts
• Apply anti-rust treatment after assembly
• Record assembly data and adjustment processes

5. Debugging Operating Rules

5.1 No-Load Debugging

• Manually close mold, check smooth operation of all mechanisms
• Check slides, lifters, and ejection mechanisms for proper positioning
• Check hot runner system for normal heating
• Check cooling system for normal water flow

5.2 Load Debugging

• Trial molding on injection molding machine, check product formation
• Check for short shots, flash, sink marks, warpage, and other defects
• Adjust assembly clearances and process parameters based on trial results
• Record trial molding parameters and product defects

5.3 Debugging Safety

• Reaching hands into the mold during debugging is strictly prohibited
• Removing safety guards during debugging is strictly prohibited
• At least two people must be present during debugging
• Clean up the site after debugging is completed

6. Repair and Maintenance Rules

6.1 Daily Maintenance

• Check mold action for smoothness every shift
• Check cooling system for leaks every shift
• Check hot runner system for normal operation every shift
• Clean mold surfaces every shift

6.2 Periodic Maintenance

6.3 Repair Rules

• Must cut off power and shut off air supply before repair
• Must confirm mold has cooled before repair
• Must use dedicated tools during repair
• Must perform trial molding verification after repair
• Repair records must be completely preserved

7. Quality Rules

7.1 Assembly Quality Standards

7.2 Quality Records

• Assembly records: Assembly date, assembly personnel, assembly data
• Debugging records: Trial molding parameters, product defects, adjustment content
• Repair records: Repair date, repair content, replaced parts
• Maintenance records: Maintenance date, maintenance content, maintenance personnel

7.3 Quality Responsibility

• Assembly personnel responsible for assembly quality
• Debugging personnel responsible for debugging quality
• Repair personnel responsible for repair quality
• Implement quality traceability system

8. Professional Conduct Rules

8.1 Work Attitude

• Serious and responsible, striving for excellence
• Comply with discipline, obey arrangements
• Unity and cooperation, mutual support</