influence of the critical rake angle in the machining of plastics.

Influence of the critical rake angle in the machining of plastics by Archibong Edem Young Download PDF EPUB FB2

A. YOUNG, “The Influence of Critical Rake Angle in the Machining of Plastics”, PhD thesis, The Queen's University of Belfast ().Author: R. Crawford, B. Hinds, C. O'Donnell, K.

Siew. The influence of the critical rake angle in the machining of plastics. Author: Young, A. ISNI: Awarding Body: Queen's University, Belfast, Current Institution: Queen's University Belfast Date of Award: Availability of Full Text. 5. Machining of plastics Optimum cutting conditions It is always desirable to obtain a continuous chip to avoid generating heat and deformation of the work material during cutting [10].

To accomplish this it is desirable to cut with tools having a critical rake angle or larger rake angle, which produces con- tinuous chips and minimum Cited by: There are two different methods for attacking the tooling design problem associated with machining abrasive plastics.

The first involves using a high rake angle and high clearance angle to allow the bit to cut freely and aggressively and to reduce the amount of heat produced during the cutting operation. Zong et al. predicted the critical cutting parameters, including the critical thickness of uncut chips, depth of cut, the feed rate of the tool and rake angle.

However, a tool with a curvilinear cutting edge is used here, and the rake angle is limited to 60°.Author: Tadeusz Mikołajczyk, Hubert Latos, Danil Yu.

Pimenov, Tomasz Paczkowski, Munish Kumar Gupta, Munish. Fig. 2 shows a cutting test (a) and a schematization (b), in which the cutting angles (clearance angle α and rake angle γ), the cutting speed (vc), the fibre orientation angle, θ, and the principal cutting and thrust forces (Fp and Ft) are videnced.

Fig. 2: a) Orthogonal Cutting apparatus; b) Scheme of the machining. This may be the optimum rake angle for plastics to obtain the most accurate parts. The value of the critical rake angle is in- fluenced by the frictional behavior of chips on the rake surface of a tool." In the present case, for PVC Plastics, this crit- ical rake angle was found to lie between 5 and 10 deg.

positive. Published by Elsevier B.V. Peer-review under responsibility of the scientific committee of the 2nd CIRP Conference on Composite Material Parts Manufacturing. 2 d CIRP Conference on Composite Material Parts Manufacturing Influence of cutting edge radius on process forces in o thogonal machining of carbon fibre reinforced plastics (CFRP.

Tools with a face angle of γ = 20° machine the material with a feed force of 4–10 N, tool model N with a rake angle of γ = 30° shows a feed force of F f = N. Feed force reduces with increasing clearance angle from α = 7–14°, a further increase to α.

Using molecular dynamics simulation, we study the cutting of an Fe single crystal using tools with various rake angles α.

We focus on the ()[] cut system, since here, the crystal plasticity is governed by a simple mechanism for not too strongly negative rake angles. In this case, the evolution of the chip is driven by the generation of edge dislocations with the Burgers vector b = 1 2.

Rake angle (α) in Figure (b) is defined as the angle that rake face of the tool makes with the normal direction of the workpiece. in Figure (a) is clearance angle of the tool. Clearance. (thermoset plastics or ceramics) •Workpiece materials with hard inclusions or impurities or structures such as graphite flakes in gray cast iron •Very low or very high cutting speeds •Large depths of cut or Low rake angles •Lack of an effective cutting fluid or low machine tool stiffness.

Figures, tables, and examples are included in order to discuss topics related to machining including cutting with a tool, chip formation, critical rake angle, ultraprecision diamond turning. The influence of the machining parameters on both the dust size and surface quality is investigated.

An increase in the rake angle of the cutting tool insert was found to localize the extent. Reliable machining of carbon fiber-reinforced plastics (CFRP) is the key for application of these lightweight materials.

Due to its anisotropy, CFRP is a very difficult material to machine because of occurring delamination and fiber-pullouts.

The tool design is especially crucial to minimize and to avoid these processing errors. In this paper a process analysis for drilling is shown for better. to analyze the effect of variable rake angle, helix angle and clearance angle on machining polyetheretherketones (PEEK) engineering plastic material, as depicted in Table 1.

Table 2 lists the rake angles, helix angles and clearance angles designed for the experiment. In this experimental study, carbide tool (K10) having different tool nose radius and tool rake angle is used.

Experiments are conducted based on the established Taguchi’s technique L18 orthogonal array on a lathe machine. It is found that the depth of cut is the cutting parameter, which has greater influence. Lead angle is the approach angle of the cutting edge as it enters the lead angle controls the direction of the radial cutting force and axial cutting force.; Rake angle is the incline of the top surface of the cutting edge that makes contact with the rake controls the degree of cutting forces and cutting edge strength.

Clearance angle is the angled relief behind the. The cutting mechanism is analysed using a modified shear angle approach and assuming the minimum energy criterion. From cutting tests shear stress is estimated and hence cutting forces calculated.

The presence of a critical rake angle at which normal force equals zero has been confirmed. The normal rake angle of the kth element is dependent on the radius distance by tan α nr = tan β 0 (r 2 k −ω 2 sin 2 ε/2)−Rω sin ε/2 cos ε/2 R sin ε/2 r 2 k − ω 2 (8) The elemental. Collection of selected, peer reviewed papers from the 12th International Conference on High Speed Machining (12th HSM), October, Nanjing, China.

The 81 papers are grouped as follows:Chapter 1: Mechanism and Technology of High Speed MachiningChapter 2: Micro-Machining and Non-Traditional Machining TechnologiesChapter 3: Recent Developments in High Speed Machine .The anisotropy of fiber-reinforced plastics heavily influences the chip formation and cut quality during machining.

Fiber arrangement is found more dominant than the often stressed cutting conditions.Machining and Grinding Plastics ReviewEngineers Edge. A zero or slightly negative back rake and a relief angle of 8 to 12 should be used on machine cutting tools.

For thermoplastics machine tool cutting speeds generally range from to ft/min (75 to m/min) and for thermosetting plastics from to 1 ft/min ( to m/min).