Konteks kejuruteraan
Secondary machining can refine bores, faces or datums after molding when the assembly needs a relationship that is difficult to hold directly from the tool.
The benefit must be weighed against extra handling, fixturing and the possibility of releasing molded-in stress. Machining also changes the datum chain if the gear tooth form remains as molded.
Secondary machining is most valuable when it controls a specific relationship that the molding process cannot hold economically. Typical candidates are precision bores, bearing seats or mounting faces. If the gear is fixtured from a cosmetic outer surface, however, machining may introduce a new eccentricity. The fixture should locate from a stable molded datum that has a known relationship to the teeth.
Apa yang perlu disampaikan oleh lukisan itu
Identify exactly which feature is machined, which molded surface locates the part in the fixture and which dimensions are inspected afterward.
Letakkan input ini pada lukisan terkawal, spesifikasi atau lampiran RFQ jika boleh. Mengekalkannya daripada thread mesej tidak formal menjadikan perbandingan pembekal dan semakan kemudian lebih mudah diuruskan.
Kajian risiko
Adding a machined bore without a coherent tooth-to-bore datum can improve diameter size but not runout.
Penerimaan sampel
Use a fixture and inspection plan that references the functional gear datum structure.
For Secondary Machining of Molded Plastic Gears, close the DFM loop by updating the controlled CAD/drawing and sample plan. A recommendation that never reaches the released revision cannot be inspected consistently in production.
Daripada semakan reka bentuk kepada RFQ
Before requesting a price for secondary machining of molded plastic gears, identify the current drawing revision, production quantity, material constraint and the feature that most strongly affects function. Ask the supplier to flag any deviation from those inputs in the quotation so technical alternatives stay visible.
Kajian reka bentuk praktikal untuk keputusan ini
Secondary machining can improve a final bore, datum, face or thread, but it changes the process chain. Define the datum used to locate the molded part, expected stock allowance, clamping method and how the machined feature relates to the gear teeth or molded interface.
Rekodkan andaian pada lukisan atau RFQ supaya pembekal boleh mengesahkannya sebelum sebut harga. Apabila nilai tidak diketahui, kenal pasti ia sebagai item kejuruteraan terbuka dan bukannya menyalin nombor katalog generik yang mungkin tidak sepadan dengan pemasangan.
Lembaran kerja pengesahan
- Molded datum used for setup
- Stock allowance
- Machined feature tolerance
- Clamp distortion risk
- Burr / stress / surface requirement
- Final inspection after machining
Gunakan sampel pertama untuk menutup titik-titik ini dengan bukti dimensi dan semakan fungsi yang berkaitan. Sebarang sisihan yang diterima hendaklah direkodkan dalam semakan terkawal sebelum pengeluaran berulang.
