Tool Wear Mechanism in Continuous Cutting of Difficult-to-Cut Material under Dry Machining

Abstract

Wear mechanism on the flank of a cutting tool is caused by friction between newly machined surface and the cutting tool, which plays predominant role in determining tool life. Detailed study on wear mechanism at the cutting edge of carbide tools were carried out at cutting speed of 55 – 95 m/min, feed rate of 0.15 – 0.35 mm/rev and depth of cut of 0.10 – 0.20 mm. The wear on the cutting tools was occurred predominantly on the nose radius, as effect of lower feedrate and nose radius selected. Various wear observed on both coated and uncoated cutting tool such as abrasive wear, adhesive wear, adhering chip on the cutting edge, flaking, chipping, coating delamination of coated tool, crack and fracture. The abrasive wear predominantly occurred on the flank face while the flaking on the rake face. Abrasive wear occurred at nose radius due to the depth of cut selected was low therefore, the contact area between the cutting tool and the workpiece material was small. Adhesion or welded titanium alloy onto the flank and rake faces demonstrated a strong bond at the workpiece-tool interface. The adhesion wear takes place after the coating has worn out or coating delamination has been occurred. The crack occurred possibly due to machining at high cutting speed and high depth of cut. Cutting at high cutting speed caused more heat generated at the cutting edge and at high depth of cut caused more cutting forces on the insert.

Surface Roughness Values of Magnesium Alloy AZ31 When Turning by Using Rotary Cutting Tool

“…As stated by previous researcher that nose radius and feed rate have a significant correlation to surface texture of new machined surface when machining super alloy materials [10]. Meanwhile, Gusri, et.al [9] found that when machining super alloy material, surface texture of machined surface formed were affected by worm tool. …”

“…The feed rate directly effect on feed mark at the machined surface. Beside of the feed rate, wear on the tool surface also contribute on the feed mark on the new machined surface [9]. …”

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“…Rata-rata pemesinan basah (wet machining) masih banyak digunakan pada industry otomotif (Tonshoff, et.al, 1997) [2]. Pemesinan basah adalah sejumlah cairan dialirkan ke kawasan pemotongan bertujuan untuk menurunkan suhu pemotongan dan melumasi bagian-bagian pemesinan sehingga diharapkan permukaan pemesinan memiliki integritas permukaan yang dapat meningkatkan masa pakai alat potong (life time) [3,4].…”

“…Pada proses pemotongan berlangsung sisi potong alat potong dan benda kerja saling berinteraksi sehingga terjadi kenaikan temperatur pemotongan [3,4]. Walaupun temperatur pemotongan sebesar 80% terbawa oleh tatal/geram yang mengalir namun akibat alat potong dan benda kerja terus bersinggungan/bergesekan maka sisi alat potong akan menjadi panas dan mengalami abrasi [5].…”

PENGARUH KECEPATAN POTONG TINGGI PADA PEMOTONGAN PADUAN ALUMINIUM 6061 TERHADAP KEUTUHAN LAPISAN PAHAT KARBIDA BERLAPIS BAHAN (TiAlN/TiN)

“…Kinerja lapisan berbahan Titanium Nitrida (TiN) yang terdapat pada alat potong tidak sesuai dengan fungsinya bilamana memotong paduan Titanium Ti-6246 pada operasi milling kecepatan potong (Vc) 55 m/menit, gerak makan (f) 0,1 mm/gigi dan kedalaman pemakanan (a) 2 mm didapati lapisan mengalami pengelupasan di awal proses pemotongan (initial wear) dan disimpulkan sebagai akibat dari reaktifitas yang tinggi pada Titanium Ti-6246 selama proses pemotongan berlangsung [6]. Temuan lain yang berkaitan dengan pengelupasan pelapis terhadap bahan dasar alat potong di awal pemotongan juga pada bahan paduan Titanium dengan operasi bubut dengan kecepatan potong (Vc) 55 m/menit, gerak makan (f) 0,15 mm/put dan kedalaman potong (a) 0,10 mm [2].…”