Full Process for Custom Non-Standard Parts

1. Drawing Receipt and Review
   The first step in custom non-standard manufacturing is not starting the machines, but reviewing the drawings.
   Upon receiving drawings, a professional factory conducts a comprehensive review to eliminate risks that could lead to rework later:

• Verify complete specifications: material grade, hardness requirements, surface roughness, tolerances, and critical geometric tolerances.
• Assess design feasibility: check for inaccessible machining areas, bending interference, or dimensional inconsistencies.
• Confirm special requirements: heat treatment, passivation, anodizing, sealing specifications, and assembly requirements.
• Verify delivery standards and deadlines.
  Industry Insight: Small workshops often start machining immediately upon seeing the drawings, whereas large factories review them first to propose optimizations and mitigate risks—this is the root cause of the difference in quality.

2. Process Breakdown and Plan Finalization
   After the drawing review, engineers analyze the part’s structure to devise the optimal machining strategy—essentially the “problem-solving approach.”
   Key tasks include:

• Selecting appropriate equipment: CNC lathe, 3-axis/4-axis/5-axis machines, grinders, or sheet metal processing
• Determining the process sequence: e.g., turning before milling, roughing before finishing, machining before heat treatment
• Allowing for appropriate machining stock to mitigate deformation risks
• Evaluating complex structures: deciding between integral forming versus splitting and welding
  Key reasons for price variations: Different factories employ different process plans; labor hours, equipment, and workflows vary significantly, leading to vastly different final prices.

3. Programming and Tooling/Fixture Preparation
   Non-standard parts lack universal molds or programs; everything must be customized from scratch:

• One-on-one manual programming and toolpath optimization by CNC engineers
• Customization of specialized jigs, fixtures, and positioning tooling
• Equipment setup, tool setting, leveling, and first-article trial cutting
  This is the primary reason why the unit price for small-batch, non-standard parts is relatively high: programming, tooling, and setup represent one-time investments; the smaller the order volume, the higher the cost allocated to each individual unit.

4 Material Preparation and Pre-processing
Prepare the raw materials required for part machining, including metals, plastics, etc.
Upon arrival at the facility, raw materials require pre-processing:

• Cutting, sawing, and blanking
• Removal of oxide scale, impurities, and oil/grease
• Pre-treatment of hard materials and materials requiring subsequent heat treatment

5. Rough Machining and Rapid Shaping
   Utilizes deep cuts and high feed rates to rapidly remove excess stock and quickly form the part’s basic shape, hole locations, cavities, and contours.
   Core objectives of rough machining: establishing the form, removing excess material, and relieving internal metal stresses.
   Rough and finish machining stages must be separated for all precision parts to prevent heat-induced deformation and residual stress caused by single-pass cutting, thereby laying the foundation for precision in the subsequent finishing stage.

6. Aging, Cooling, and Stress Relief
   After rough machining, parts exhibit high temperatures and significant internal stress; proceeding directly to finish machining makes them highly susceptible to subsequent deformation and dimensional errors.
   Standard procedures incorporate time for cooling, aging, and stabilization. For certain steel components, large parts, and thin-walled sections, vibration aging treatment is additionally employed to thoroughly relieve stress and ensure long-term dimensional stability of the finished product.

7. Precision finishing: locking in accuracy and appearance
   This is the critical step that determines whether a part meets specifications.
   By employing shallow cutting depths, constant feed rates, and light finishing passes, we correct residual errors, tool marks, and deformation from rough machining to precisely achieve:

• Dimensional tolerances (IT6–IT9 precision grades)
• Geometric tolerances (such as roundness, coaxiality, perpendicularity, and parallelism)
• Surface roughness and finish quality
  High-precision holes, sealing surfaces, locating surfaces, and mating surfaces all undergo final finishing during this stage.

8 Post-Processing Operations
Surface and material property treatments are matched to drawing specifications to ensure optimal functionality and aesthetic quality:
*Rust and Corrosion Protection: Stainless steel pickling, passivation
*Aesthetic Finishing: Polishing, brushing, sandblasting
*Hardening Treatments: Quenching, tempering, quenching and tempering (Q&T)
*Surface Coating/Plating: Anodizing, blackening, galvanizing, chrome plating
All post-processing is executed strictly according to drawing standards—without shortcuts or downgrades—to prevent issues such as rusting, wear, or insufficient hardness.

9 Full-Dimension Quality Inspection
Non-standard parts lack universal acceptance criteria; the engineering drawing serves as the sole standard.
Upon completion, quality inspectors conduct comprehensive checks against the drawings:
*Standard Dimensions: Caliper and micrometer measurements
*High-Precision Dimensions: Dial indicators, height gauges, and CMM (Coordinate Measuring Machine) inspection
*Verification of hardness, surface roughness, appearance, hole positioning, and fit
Quality is controlled through a tiered process involving first-article inspection, random sampling, and full inspection; compliant products are warehoused, while non-compliant items are reworked or scrapped.

Custom manufacturing of non-standard parts is never merely about “machining”; it is a comprehensive service encompassing design interpretation, process planning, precision production, quality control, and final delivery.