Fixture Manufacturing Process Of Us

Some of my customer want to know how we process fixture, how we should cooperate to produce sophisticated fixture products that meet usage requirements, so i will introduce in this article.

Fixture Manufacturing Process

The fixture manufacturing process is a systematic project that transforms a concept into a physical object, closely revolving around the technical essentials mentioned earlier. The following is the complete manufacturing process for a fixture, from design to delivery.

The entire process can be clearly divided into five main stages. The chart below illustrates its core steps and iterative relationships:

Stage 1: Requirement Analysis & Conceptual Design

This is the foundational stage that determines the success of the fixture design.

1. Understand the Part and Process:

• Analyze the Workpiece: Meticulously study the workpiece drawings (2D/3D) to clarify its material, weight, structural rigidity, key features, machining accuracy requirements, and datums.

• Understand the Process: Define the machine tool model (table size, travel, T-slot location), machining operation (milling, drilling, boring, etc.), cutting parameters (estimating the magnitude and direction of cutting forces), and takt time requirements.

2. Define the Fixture Concept:

• Locating Scheme: Based on the "Six-Point Principle," determine which locating elements (pins, blocks, surfaces) to use and where to locate to ensure the workpiece's correct position in space.

• Clamping Scheme: Determine the number and position of clamping points and the clamping method (manual, pneumatic, hydraulic). Select the clamping mechanism (clamp plates, jaws, modules, etc.) to ensure reliable, efficient clamping without causing part deformation.

• Fixture Type Selection: Decide whether to use a dedicated, modular, or adjustable fixture.

• Preliminary Layout: Create sketches or simple 3D models to plan the general structure and spatial layout of the fixture body (base plate), ensuring no interference with the machine tool and cutting tools.

Stage 2: Detailed Design & Review

This stage transforms the concept into actionable production documents.

1. 3D Modeling & Interference Check:

• Use CAD software (e.g., SolidWorks, CATIA, NX) for detailed 3D modeling.

• Model all parts precisely and perform a dynamic interference check to ensure moving components (e.g., cylinders, linkages, clamp plates) do not collide with the workpiece, fixture body, or tools during movement.

2. Engineering Drawing Creation:

• Fixture Assembly Drawing: Shows the assembly relationship of all components, key dimensions, technical requirements, and a bill of materials (BOM).

• Part Drawings: Create detailed 2D drawings for every part that requires manufacturing,标注所有尺寸、公差、几何公差（如平面度、垂直度）、表面处理（如发黑、镀铬）和材质要求。 (Note: This section was already in English in the original response. If translation is needed: ...annotating all dimensions, tolerances, geometric tolerances (like flatness, perpendicularity), surface treatment (like blackening, chrome plating), and material requirements.)

3. Design Review:

• Conduct a formal design review involving design, process, manufacturing, and user departments.

• Review Focus: Rationality of the locating and clamping scheme, ability to guarantee precision, structural rigidity and strength, operational safety and convenience, manufacturing cost and lead time.

• Modify and optimize the design based on feedback, then finalize and freeze the drawings.

Stage 3: Material & Component Sourcing

1. Procurement:

• Standard Components: Purchase standard parts from the BOM, such as locating pins, bushings, bolts, springs, cylinders, hydraulic cylinders, quick-release couplings, etc.

• Raw Materials: Purchase the required steel (e.g., A3 steel, 45# steel) or aluminum for the fixture body and base plate.

2. Outsourced/External Parts:

• Arrange external suppliers for key parts requiring special processes (e.g., precision wire EDM, heat treatment) in advance.

Stage 4: Machining & Assembly

This is the core manufacturing stage where drawings become physical objects.

1. Machining:

• Rough Machining: Perform milling, planing, turning, etc., on the fixture body and large support members to remove the bulk of the material.

• Heat Treatment: Apply processes like quenching to key wear-prone parts (e.g., locating pins, clamp blocks) to increase hardness.

• Precision Machining: This is the critical step for ensuring accuracy. Use precision milling, grinding, etc., to machine key locating surfaces, mounting surfaces, and hole patterns. Jig boring machines or CNC machining centers are often used for high-precision hole location machining.

2. Bench Work & Assembly:

• Positional and dimensional accuracy between locating elements.

• Geometric tolerances (flatness, perpendicularity) of key surfaces.

• Bench Fitting: Includes hand-scraping critical locating surfaces to improve contact ratio and accuracy, deburring, and chamfering.

• Assembly: Assemble the machined parts and purchased components according to the assembly drawing. Install locating elements, clamping mechanisms, pneumatic/hydraulic lines, etc.

• Accuracy Inspection: During and after assembly, use inspection tools like Coordinate Measuring Machines (CMM) and height gauges to critically check:

Stage 5: Debugging & Final Acceptance

This is the final stage to verify if the fixture meets all requirements.

1. Sample Part Installation & Debugging:

• Use one or more qualified sample parts (or first-article workpieces) for actual loading and clamping.

• Check for smooth locating, reliable and effective clamping, and convenient operation.

• For powered fixtures, check that air/hydraulic lines are clear, leak-free, and that actions are smooth and complete.

2. Machine Trial Run:

• Install the fixture on the target machine tool.

• Dry-run the program (without tools or using a dummy tool) to check for interference between the fixture and the machine spindle, tool changer, or automatic tool magazine.

• Perform an actual test cut, machining one or more workpieces.

3. Inspection & Validation:

• Perform a comprehensive dimensional inspection on the workpiece(s) from the test cut. All dimensions and geometric tolerances must be within the drawing's specified range.

• If the workpiece is non-conforming, analyze the root cause: Is it fixture locating error, clamping deformation, or another issue? Then make adjustments or modifications to the fixture.

4. Final Delivery:

• Final Accuracy Report: Provide an inspection report for the fixture's key dimensions.

• Operation Instructions: Create simple illustrated instructions for operators on how to correctly use and maintain the fixture.

• Physical Handover: Deliver the complete fixture, spare parts, and relevant documentation to the production department.

• After the fixture passes acceptance, complete the following:

This process ensures the fixture is controlled from conceptual design to final product, maximizing its functionality, reliability, and economy.

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