Machining tips and precautions in grooving and cutting off

The cutoff and grooving process is an important part of CNC turning machining and presents many unique challenges. During the machining process, the limitations of machine tool and tool rigidity, cooling conditions, programming techniques, tool performance and many other factors can cause problems for machining efficiency, quality and safety. At the same time, cut off the groove machining area is very narrow, chip removal and control, blade safety has high requirements, high reliability tool material and excellent groove structure has become an important indicator of the pursuit of the market, and high-performance cut off the groove cutting tool with superb machining process technology, to solve the cut off the groove of high-efficiency and high-quality machining of an important way. We are here to talk about the selection of grooving cut-off tool skills and methods.

Cutting and grooving tool applications and processing characteristics

Cutting tools and grooving tools are widely used in machining, automobile manufacturing, metal processing, electronics manufacturing and other fields. For example, automobile manufacturing uses cut-off tools to groove and process automobile parts, and in bearing processing, grooving tools are used to process the grooves of bearings and so on. Cut off and grooving tools play an irreplaceable role in machining and production, and their superior characteristics and wide range of applications contribute to the development and progress of the manufacturing industry.

At the same time, the cut-off and cut-off process is characterized by a very narrow cutting zone, which poses a problem in controlling the chips generated during machining. Especially in the cut-off process, the tool is surrounded by the workpiece material on both sides during cutting, which restricts the chip discharge path. At the same time, the thin chips produced in cut-off and grooving tend not to break, and uncontrolled ribbon chips can lead to chip clogging, damage to the workpiece, and a risk to operator safety. In addition, chip control problems can prevent the implementation of unattended or "fully automated" machining.

In addition, high chip deformation, high cutting forces, concentrated cutting temperatures and poor tool rigidity are also important factors in cut-off and grooving. Select a more optimized processing technology solutions and high-performance cut-off cutter tool products is an important way to solve the cut-off groove processing problems.

Cut off the groove processing technology

Cutting groove or grooving insert front for the main cutting edge, both sides for the sub-cutting edge, cutting process to transverse feed mainly, the main cutting edge to withstand a larger cutting force, at the same time, due to the cutting of the fracture and discharge is more difficult, cutting edge cutting temperature is high, coupled with the impact of insufficient cooling factors, the safety of the cutting process is facing a greater challenge. Therefore, in the face of different machining requirements, the appropriate machining process technology should be selected so as to realize highly efficient and safe cut-off groove machining.

●Selection of working condition system

There are some specific setting recommendations for cut-off and grooving tools. When setting up the tool, care should be taken so that the insert is truly perpendicular to the axis of the workpiece. This minimizes axial forces on the tool and prevents rubbing the sides of the insert. For tool position, the center height of the cutting edge should be as close as possible to the center of the workpiece, with a deviation of ±0.1 mm or less, which also prevents excessive pressure on the tool, which could shorten tool life.

In addition, the stability of the working conditions for the cut-off groove processing is critical. Stable cutting conditions can not only ensure high processing efficiency, but also achieve better processing quality. Therefore, for CNC lathes, ensure that the grooving position is as close as possible to the chuck position, and at the same time, on the premise of ensuring that the workpiece is not interfered with, try to use a larger diameter of the toolpost and the smallest tool overhang.

● Selection of cutting parameters

The cutting parameters of the cutting and grooving tools are different from those of ordinary turning. If the spindle speed is constant, the cutting speed of the cut-off tool slows down to zero when it reaches the center of the bar. The slowed down speed puts heavy pressure on the tool and may cause the workpiece material to adhere to the cutting edge. Therefore, the feed rate should be reduced as the tool approaches the center of the part.

The inserts used in the cutting and grooving process are usually narrow, while the cutting process is unstable due to the predominance of lateral feed. Cutting parameters can be effectively adjusted to achieve the chip deformation tend to optimize, reasonable cutting speed and feed can effectively achieve the chip shape of the hairline, and different groove type inserts generally have the most appropriate range of cutting parameters. The following is the common chip shape in the process of cutting off the groove.

● Reasonable selection of cooling system

Reasonable selection of cooling system can effectively improve the chip breaking and cooling effect of the cut-off groove, at present, ordinary water cooling is the most common form of cooling for cut-off groove machining. However, pouring coolant is usually unable to generate sufficient pressure to reach the cutting zone in cut-off and grooving applications. Also, pouring coolant nozzles can be difficult to locate to direct the coolant to where it is most needed. Finally, the relatively weak pouring coolant stream may be converted to vapor in the cutting zone, which effectively creates a barrier that prevents the heat generated during the cutting process from escaping. As a result, high-pressure jet cooling has become a sought-after form of cooling for cut-off grooves in recent years. For best results, the high-pressure coolant must be delivered at regular intervals and as close to the cutting zone as possible to ensure chip breakage and optimized cooling, resulting in improved cutting stability and longer insert life.

● Optimization of machining process

Selecting the appropriate machining process and method in the cut-off groove machining can not only optimize the machining process, but also improve the machining efficiency and quality of machining. Different grooving profiles choose different machining processes, so it is necessary to combine the characteristics of the groove and the operability of the process. For the general shape of the groove, direct cutting can be; face deeper grooves, need to use pecking cycle instructions for chip processing; wider grooves are selected grooving + cross turning method for processing; arc groove in the processing as far as possible to use the round head of the lathe tool and the tip of the tool arc half-finish compensation instructions for processing.

Richconn's new generation of new cut-off grooving series products

In view of the characteristics of cut-off and grooving, Richconn has developed GT, CT and RM cut-off and grooving product systems, which can effectively realize the machining process requirements of cut-off, grooving and profiling, and at the same time ensure the safety of the cutting process, high quality and long tool life.

● GT Grooving Series - Highly efficient cut-off tools

This is a series of inserts for grooving and cut-off, which meets the needs of high-efficiency (large feed) grooving. The groove type has the following characteristics:

(1) The groove design with both edge strength and sharpness is suitable for large feed cutting and grooving of carbon steel, alloy steel and cast iron;

(2) The design of large chip holding space ensures smooth flow of cutting as well as proper storage of coolant to reduce the cutting temperature in the edge area.

● CT groove series - grooving and cross-turning groove machining

(1) Unique chipbreaker design meets the requirements of chipbreaking and chip control for grooving and cross-turning machining;

(2) Multi-linear side edge design ensures smooth chip removal under different cutting conditions during cross-turning machining;

(3) Variable cutting edge width design and special edge processing technology ensure cutting sharpness and edge strength at the same time.

● RM Groove Series--Profile Turning

(1) The design of eight equal bumps around the circumference ensures good chip control during profiling and better surface quality;

(2) Double front angles and wide cutting edge band design, taking into account the cutting sharpness and edge strength.

The GT, CT and RM groove types of the whole generation are matched with the new grades HR8225 and HR7225 to solve the dual requirements of high efficiency and long service life for various types of grooving processing. Among them, HR8225 adopts new cemented carbide matrix composition, with high strength, excellent wear resistance and reliable toughness, and the composite multi-layer CVD coating with high-strength directional growth of alumina, with excellent wear resistance, while HR7225 adopts new non-metallic modified nano-gradient composite structural coatings, with ultra-high nano-hardness, good cohesion failure resistance, and film-base bonding, with further enhancement of safety. Further enhancement of safety.

Richconn Cutting and Grooving Case Sharing

Case 1

Processing name and material: gearbox gear seat 40Cr (21~24HRC)

Machining equipment: CNC lathe

Insert used: HR8225/QCMB4004-CT

Competitor: Imported 4mm slot insert

Processing parameters: vc(max)=150m/min f=0.2mm/r ap=2mm

Cooling method: water cooling

Processing form: end face grooving + turning

Use effect: Richconn HR8225/QCMB4004-CT can meet the single tip processing 80 pieces of workpiece tool change standard, the original use of imported 4mm groove insert tool change standard is 60 pieces / edge.

Figure machining parts appearance

Case 2

Workpiece and material: nut 38CrSi (280~300HB)

Machining equipment: CNC lathe

Insert used: HR7225/QCMB3002-GT

Original insert: Japanese brand 3mm groove cutter

Processing parameters: n=1000r/min f=0.05mm/r

Processing method: cut off

Cooling method: water cooling

Use effect: Richconn HR7225/QCMB3002-GT single tip can be stabilized processing 70 pieces, the original blade single tip average life expectancy of 50 pieces, and the performance stability of Richconn products is significantly better than the original product.

Figure machining parts appearance