Advantages of Horizontal Machine Tool Processing Titanium Alloy Hinge_Hinge Knowledge_Tallsen

Currently, titanium alloy materials are extensively utilized in hinge manufacturing due to their unique properties. However, their low thermal conductivity poses a challenge during the cutting process. Inadequate chip removal can lead to increased tool wear, shortened tool lifespan, and poor surface quality. This article aims to provide a detailed discussion on the efficient processing method using a horizontal machine tool for a specific machine part.

Manufacturability Analysis of Parts:

The part under consideration has a complex structure with profiles in multiple directions, requiring collaboration between multiple workstations for completion. It is made from die forging using TA15M material, with outer dimensions of 470 x 250 x 170 and weighing 63kg. The part dimensions are 160 x 230 x 450, weighing 7.323kg, and the metal removal rate is 88.4%. The part's structure features a hinged design with profiles in six directions, making it highly irregular. The lack of an open clamping area and poor stability necessitate processing the part in multiple stations. The key challenge in the process plan is ensuring the wall thickness of the parts. The deepest groove in the part is 160mm, with a small width of only 34mm and a corner radius of R10. The assembly of these corners presents an overlapping relationship, requiring strict dimensional maintenance. CNC machining requires tools with a high length-diameter ratio, which poses another processing difficulty due to poor tool rigidity.

Determination of Processing Plan:

3.1 Machining by Vertical CNC Machine Tool:

Since the part has profiles in all directions, special milling clamps are necessary for processing at different angles. The part is first processed using a five-coordinate vertical machine tool, followed by turning to a horizontal machine tool for end processing. The different angles are achieved using fixture positioning surfaces, ensuring CNC machining compliance. Part A serves as the benchmark for subsequent processing and requires a set of special fixtures. However, limitations imposed by the five-coordinate vertical swing angle inhibit processing part B, necessitating two clamping operations with two sets of fixtures. For part C, three sets of fixtures are required for three clamping operations. Parts D and E need to be transferred to a horizontal machine tool, where special fixtures are used for two clamping operations. Multiple fixtures increase the chances of machining errors, such as fixture positioning errors, fixture manufacturing errors, and part clamping errors. These errors accumulate, making it challenging to guarantee part size and increasing manufacturing costs. Moreover, multiple fixture preparations prolong processing times and production cycles. Considering the swing angle limitations of the five-coordinate machine tool, this part is not suitable for vertical CNC machining.

3.2 Machining by Horizontal CNC Machine Tools:

(1) Selection of CNC Machine Tools:

The forging's outer dimensions, 470 x 250 x 170, make it suitable for machining on small worktable horizontal machine tools. Based on available equipment, a CNC five-coordinate high-rigidity horizontal machining center is chosen. This machine tool offers excellent rigidity with two interchangeable worktables, enabling preparation during processing and enhancing work efficiency. The machine tool's A angle can swing within 90/-90 degrees, while the B angle can swing through 360 degrees. Efficient cooling equipment aids quick and timely chip removal, prolonging tool life.

(2) Establishment of Processing Flow:

Part A, including its planar shape and reference hole drilling, is processed using the five-coordinate vertical machine tool, eliminating the need for fixtures. The horizontal machine tool processes parts D and E, leaving a 5mm process allowance on the bottom surface for subsequent processing rigidity. For part B, the inner groove and lug shape are fully processed in place. Part C involves rough and fine milling of large and small lugs and notches. Finally, both ends require supplementary milling to remove process allowances. Surface A serves as the positioning surface for all processing parts, requiring only one set of fixtures to rotate through the worktable for completing each part. This CNC approach eliminates conventional supplementary processing, enabling high-precision digital processing.

Compilation of Processing Program:

(1) Enhancing Process System Rigidity:

During programming, careful consideration is given to part clamping positions and the arrangement of pressure plates to enhance the rigidity of the process system.

(2) Program Compilation for Part Ends:

The part's end has a depth of 90mm with an R8 corner. To ensure process system rigidity, a 5mm layering approach is employed during programming. The program reduces speed by 50% for corners, using the same specifications for rough and fine processing. The final step involves supplementary milling of corners using a φ16R4 milling cutter.

(3) Program Compilation for Deep Grooves:

Deep groove programming involves three tool series. The upper section is processed using a φ30D4 milling cutter with a depth of 50mm. The middle section employs a φ30R4 cutting tool with a depth of 100mm, and the bottom section uses a φ30R4 cutting tool with a depth of 160mm. The side is processed using a φ30R4 milling cutter in place, with supplementary milling of angles using a φ20R4 milling cutter. When programming lug surfaces, the shortest tool is used by changing the tool axis direction.

(4) Program Compilation for Lugs and Notches:

To process small lugs and slots, a layering approach is employed using a φ10R2 milling cutter for rough milling. A 1mm margin is left on each side, followed by separate rough and fine milling for finishing. Single-side machining for finishing aids in ensuring lug thickness and notch width. The program's center track is compiled based on the median value of the part's tolerance zone. Considering a tolerance of -0.2 for the notch, the program includes a one-sided —0.05mm offset preparation. This approach significantly improves part qualification rates.

(5) Cutting Parameters Used in Processing:

The part's greatest difficulty lies in its groove depth, irregular structure, and small corners. The cutting tools are divided into several series to address these challenges. A short tool is used for processing the upper half, followed by a long tool for deep groove processing. Imported φ30R4 cutters are selected for roughing and finishing the part's internal shape, with tools lengths divided into multiple series for optimal results.

(6) Inspection of Processing Procedures:

VERICUT6.2 simulation software offers powerful functions for checking the accuracy of NC programs. It allows for the evaluation of cutting allowances, identification of tool collisions, assessment of machine tool interference, and examination of machining residues. By utilizing VERICUT6.2, the effectiveness of the processing program can be verified.

Through a comparative analysis of processing plans and actual processing results, it is evident that horizontal machine tools offer the advantage of completing multiple parts in a single clamping operation. This eliminates the need for multiple clamping, reducing auxiliary time and eliminating errors associated with multiple clamping. Consequently, both the processing cycle and the part's quality are improved. This experience gained from processing such complex parts using horizontal machine tools is invaluable for future similar product manufacturing.