Cutting process considerations

According to a recent international survey, users value production efficiency, process stability, trouble-free cutting, tool life predictability, and part quality consistency, and they are listed as the primary priority for the cutting process.

Cutting process challenges

The cutting process may seem quite straightforward, and it is also true, but in order to safely perform these processes while ensuring the high productivity of modern turning, it is necessary to overcome the cutting challenges. The main issues facing this are still: burrs and flash formation, chip formation and chip evacuation, vibration trends, and inconsistent and premature tool wear. Fortunately, if you choose the right tool and apply it correctly, it's not a problem today.

The first step in tool selection

First, it is necessary to establish the type of shank and the tool system that are most suitable for the process. Here, the diameter of the workpiece in particular plays a crucial role because the tool holder is directly related to the required depth of cut. Most cutting depths are within the range of 6 to 28 mm of medium processing when cutting. The deep cutting depth is 28-55mm, while the shallow cutting depth is 0.25-6mm. There are other extreme situations.

When selecting a holder, the necessary compromise between versatility and stability may occur. The related batch size and operational changes will affect the selection direction. Because tool overhangs can be set to fit different diameters, tools with adjustable blades can be used for a wide variety of workpiece diameters. On the other hand, a holder with an integral reinforcement blade is only suitable for a range of diameters, but provides maximum strength.

Between the two different cutting tool types is a universal cutting tool with screw or elastic clamping suitable for single or double-edged inserts. Here, selecting the largest shank size, such as the shank and blade height, increases the stability of the tool to accommodate changes in depth of cut. Screw clamping means the highest blade and toolholder stability, while elastic clamping can use narrow tools to increase versatility and accessibility, so that only a small amount of material can be cut and the machine power is lower.

The best blade selection step

The cutting edge is crucial. It will guide the tool during cutting and control the chip, while determining the formation of flash and burrs and more or less improve the cutting efficiency of the material. The ultimate in tool stability is the relatively thin interface between the blade and the tool holder. In order to maintain stability, good track and V-shaped blade seat structures are required, and it is preferable to use them with relatively long blades. This structure is crucial for cutting tool performance.

The blade width differs depending on the cutting depth capability of the cutting tool. Thin blades can be used for small depths of cut (workpiece diameters), while wider blades are used for large depths of cut to ensure strength.

The type of insert seat on the shank corresponds to the width of the insert, each system has its own specific range of insert widths, eg CoroCut single and double-edge systems with eight different insert widths, ranging from 1.5 to 8mm; and CoroCut 3 is suitable for shallow cutting, with 3 blade widths, ranging from 1 to 2 mm.

When selecting insert geometries and grades for the process, the most suitable combination of sharpness, strength and width of the cutting edge should be established to ensure the highest possible feed per revolution for maximum production efficiency. The sharp edge and groove shape is easy to cut, the required machine power is small, and the vibration tendency is minimized. The strong slot has a larger negative rake angle and the cutting edge is also reinforced, so it can withstand more demanding cutting and roughing operations and can achieve higher feed rates. Processing conditions and operating changes indicate the direction of the selection and there is usually a trade-off, especially when a certain degree of versatility is required, the semi-finished groove shape is a good choice. By opting for today's different inserts, various optimization possibilities are possible – Wiper inserts are used to increase surface quality and feed; enhanced insert fillets are used to obtain higher feeds Ability and safety, and good cutting control through softer cutting action and burr minimization.

For blade brand selection, cutting edge strength should be the first priority, as strength ensures the safety of the cutting process. This means that priority should be given to toughness rather than to sharper and harder grooves and grades. Followed by operational factors and processing conditions to obtain the required surface quality and feed rate, and continue to improve the grade to make it more wear-resistant, resulting in higher feed and longer tool life.

The process is made even easier by applying the latest and extensive PVD coating grades. This grade offers a versatile solution with high feed capability and is optimized for most workpiece materials. (GC1125) Inspection and Fundamental Analysis of Cutting Edge Wear During Machining Pointed to the cutting parameter adjustment or possible replacement number for best performance. The basic indicator is the cutting edge deformation, which means that the cutting edge is too tough; and the chipping of the cutting edge means that the cutting edge is too hard. Remember to use the recommended cutting parameters.

Minimize flash and glitches

Burr formation is a control issue in the cutting process and a blade selection factor. The rake angle (leading angle) of the cutting edge largely determines the formation of burrs - the 0° lead angle will generally produce the straightest cutting path and the best surface quality, but will leave burrs at the end of the cut. After the cut-off portion falls and the cutting edge passes through the center of the workpiece, the bevel edge can minimize or completely cut out the burr. Because it is easy to control the tool from deviating from the intended straight tool path, a cutting edge with a larger rake angle can have a negative effect on the straightness of the cut. For this reason, although the 10° and 15° rake angles available for low feed slot geometry should be considered in terms of sharpness, a moderately inclined edge (5°) is usually the best choice.

In limiting the formation of flash, the sharpness of the cutting edge plays an important role. Grinding the positive rake angle edge minimizes flashing, while the solid groove shape with large radiused corners tends to form burrs, especially when larger feedrates are used. In this regard, additional passes after cutting with the same tool or finishing tool may be a solution to achieve optimal production efficiency.

Other factors affecting the cutting process

Optimizing the fixture not only affects the results of the process, but also affects the degree of optimization. The basic principle is to minimize the tool overhang to obtain rigidity and ensure that the cutting edge is as close as possible to the centerline. For a good cutting method, a suitable and sufficient coolant supply and its direction are often also crucial. A knife block with integrated coolant supply is a solution; in addition coolant is supplied from below to increase tool life and improve chip control.

When cutting the bar stock, the diameter of the cut workpiece will continuously decrease, reaching zero near the center. The cutting speed is therefore significantly reduced, thereby increasing the tendency of the built-up edge formation on the cutting edge, which in turn has a negative effect on tool life. Increasing the spindle speed and reducing the feed rate by a few millimeters before passing through can compensate for this adverse effect.

The most basic optimization factors

For highly competitive cut-off applications, optimizing the feed rate is almost always one of the main priorities. Feeding largely determines the level of production efficiency, that is, the length of time required to perform the process. (Successful realization of 0.15mm feed per revolution, instead of 0.10mm, and longer and predictable tool life, there is a huge difference between the two.)

Feeding also means that chip formation can be controlled by changing the feed during cutting, dwelling or ramming. Feed rates can also be increased to minimize vibration trends when cutting speeds are reduced. The feedrate should also be set for the correct tool pressure to ensure a straight toolpath and reduce it before the end of the cut to avoid forced cuts, while ensuring its safety during intermittent cuts. Finally, it is concluded that the combination of feed, blade and holder is the most important optimization factor when cutting.

Veterinary Tablets

Antibiotic Tablets,Deworming Tablets,Vitamin Tablets,Anti Inflammatory Tablets

Henan ShowVet Industrial Co., Ltd. , https://www.cxbt-showvet.com