China Precision CNC Machining Titanium Alloy Fracture Fixation Plate Medical Implant Manufacturing Case Study

As a precision machining technician, I will share our recent processing case of titanium alloy fracture fixation plates. This batch of products is designed for maxillofacial fracture fixation surgery, requiring extremely high precision requirements and strict biocompatibility standards. Through 5-axis CNC machining centers, we achieved one-time forming processing of complex curved surfaces, providing reliable solutions for medical implant manufacturing.

The titanium alloy fracture fixation plates processed this time are used for mandibular comminuted fracture repair, with specific requirements as follows:

• Material specifications: TC4 titanium alloy (Ti6Al4V) compliant with GB/T13810 and ISO5832-3 standards, requiring complete material certificates
• Dimension characteristics: Plate length 8.5cm, width 1.2cm, thickness 0.3cm, containing 12 screw holes with hole distance tolerance controlled within ±0.05mm
• Surface requirements: Surface roughness Ra≤0.8μm, without any tool marks or burrs, edge chamfer below 0.1mm
• Special requirements: Must perfectly fit the patient's jawbone anatomical curve with error less than 0.1mm
• Delivery time: Complete from receiving CAD model to finished product delivery within 72 hours

Based on part characteristics and requirements, we developed the following machining solution:

Process route planning:

• Use JDGR400T 5-axis high-speed machining center to complete all processes in one setup
• Adopt "roughing-semi-finishing-finishing" three-stage strategy, reserving 0.15mm finishing allowance
• Select special tools for titanium alloy characteristics: φ6mm four-edge end mill for roughing, φ2mm ball end mill for finishing

Fixture design:

• Design special vacuum fixtures to prevent deformation of thin-walled parts during processing
• Adopt modular positioning system supporting quick changeover during batch production

Parameter optimization:

• Spindle speed: 8000rpm for roughing, 12000rpm for finishing
• Feed rate: 1500mm/min for roughing, 800mm/min for finishing
• Cutting depth: 0.3mm for roughing, 0.05mm for finishing

Quality control points:

• Online measurement system real-time monitoring of critical dimensions
• Full-size inspection of each product with CMM
• 100% inspection with surface roughness tester

During machining execution, we implemented strict quality control measures:

Machining process monitoring:

• Use precision tool setting instrument to ensure accurate tool length and diameter compensation
• Real-time monitoring of cutting force changes to prevent excessive tool wear
• Use special titanium alloy cutting fluid during processing, controlling temperature at 25±5°C

Quality inspection process:

• First-piece comprehensive inspection: Use CMM to inspect all hole positions and contour dimensions
• Patrol inspection frequency: Key dimension sampling every 5 pieces processed
• Final inspection standard: 100% inspection according to medical device implant standards

Problem-solving record:

• Discovered slight chatter marks on the surface of the 3rd piece: Solved by adjusting spindle speed from 12000rpm to 10000rpm and increasing feed rate to 1000mm/min
• Screw hole perpendicularity deviation: Optimized drilling process, using peck drilling method completed in three steps

Documentation:

• Complete records of processing parameters and inspection data for each product
• Provide full set of documents including material certificates, processing process reports, inspection reports

This processing task achieved significant results:

Processing data results:

• Dimension pass rate: 100% (all 12 products meet drawing requirements)
• Surface roughness: Achieved Ra0.6-0.7μm, better than customer requirement of Ra0.8μm
• Delivery time: Completed 8 hours ahead of schedule, actual processing cycle 64 hours

Customer feedback:

• Surgical team reported perfect fit between fixation plate and patient's jawbone, no intraoperative adjustment needed
• Doctors particularly appreciated the accuracy of screw holes, ensuring directional accuracy of screw implantation
• Within-batch consistency recognized, dimensional variation among 12 products less than 0.02mm

Continuous improvement:

• Based on this experience, optimized processing parameter templates for titanium alloy thin-walled parts
• Improved vacuum fixture design, reducing setup time by 30%

Through this case, we verified the advantages of 5-axis CNC machining centers in medical implant manufacturing. Key success factors for processing titanium alloy fracture fixation plates include:

• Process optimization: Reasonable tool selection and cutting parameters matching titanium alloy characteristics
• Fixture innovation: Special vacuum fixtures ensuring stability in thin-walled part processing
• Quality control: Whole-process monitoring ensuring dimensional accuracy and surface quality
• Team collaboration: Close coordination among programming, operation, and quality inspection links

This precision machining capability is particularly suitable for personalized medical implant manufacturing, enabling rapid production of matching fixation plates based on patient CT data. In the future, we will further integrate 3D printing and CNC machining technologies to provide more comprehensive manufacturing solutions for the medical field.