The importance of tool selection in machining is self-evident. Learning to choose tools can help you work more easily. Different types of cutting tools can achieve twice the result with half the effort in machining materials.
The Most Important Thing in Machining is Cutting Tools
If any cutting tool stops working, it means production stops. But it does not mean that every tool is equally important. The tool with the longest cutting time has a greater impact on the production cycle. Therefore, under the same premise, this tool should be given more attention. In addition, attention should be paid to the tools that process key components and the tools with the strictest tolerance range. In addition, tools with relatively poor chip control, such as different drills (carbide drill bits, HSS drills), grooving cutters and thread cutting end mills should also be paid attention to. Poor chip control can cause downtime.
Matching Cutting Tools to Machine Tools
Cutting tools are divided into right-hand tools and left-hand tools, so it is very important to choose the right tool.
Generally, right-hand tools are suitable for machines that rotate counterclockwise (CCW) (looking along the spindle direction). Left-hand tools are suitable for machines that rotate clockwise (CW). If you have several lathes, some clamp left-hand tools and others are compatible with both hands. Then choose left-hand tools.
For milling, people usually tend to choose more versatile tools. However, although such tools cover a wider range of processing. You also lose the rigidity of the tool immediately, increase the deflection deformation of the tool, and reduce the cutting parameters. At the same time, it is more likely to cause processing vibration. In addition, the robot for changing tools on the machine tool also has some restrictions on the size and weight of the tool. If you buy a machine tool with an internal cooling hole in the spindle, please also choose a tool with an internal cooling hole.
Matching Cutting Tools to the Material Being Machined
Carbon steel is the most common material to be processed in machining, so most cutting tools are designed based on optimized carbon steel processing. The blade brand needs to be selected according to the material to be processed. End mill tool manufacturers provide a series of cutter bodies and matching blades for processing non-ferrous materials such as high-temperature alloys, titanium alloys, aluminum, composites, plastics and pure metals.
When you need to process the above materials, please choose a cutting tool with matching materials. Most brands have various series of end mill tools, indicating what materials are suitable for processing. For example, SAMHO’s SHALP series is mainly used to process aluminum alloys, SHG series is specifically used to process high-hardness steel, and SHTI series is specifically used to process titanium alloy steel.
Properly Select Cutting Tool Specifications
A common mistake is to choose a turning tool that is too small and an end mill that is too large. A larger turning tool is more rigid. A larger milling cutter is more expensive and takes longer to cut. In general, larger tools cost more than smaller tools.
Choose Between Inserts or Regrindable Tools
The principle to follow is simple: try to avoid grinding tools. Except for a few alloy drill bits and end mills, try to choose replaceable blade or replaceable head tools if conditions permit. This will save you labor costs and obtain stable processing results.
Cutting Tool Materials and Grades
The choice of milling cutter tool material and brand is closely related to the performance of the material being processed, the maximum speed and feed rate of the machine tool. Choosing a more common tool brand for the group of materials being processed usually selects a coated alloy brand. In practical applications, a common mistake is to try to solve the tool life problem by replacing a similar material brand from another tool manufacturer. If your existing cutting tool is not ideal, then changing to a similar brand from another manufacturer is likely to bring similar results. To solve the problem, the cause of tool failure must be clearly identified.
CNC Machine Tool Power Requirements
If you buy a CNC milling machine with a power of 20hp, then, if the workpiece and fixture allow, select the appropriate tool and processing parameters to achieve 80% of the power utilization of the machine tool. Pay special attention to the power/speed table in the machine tool user manual. According to the effective power range of the machine tool power, select the end milling bits that can achieve better cutting application.
Number of Edges of CNC Cutting Tools
The principle is, the more the better. Buying a turning tool with twice the cutting edges does not mean paying twice the price. In the past decade, advanced designs have doubled the number of cutting edges on grooving cutters, cut-off cutters and some milling inserts. It is not uncommon to replace the original milling cutter with only 4 cutting edges with an advanced milling cutter with 16 cutting edges. Increasing the number of effective cutting edges also directly affects the table feed and productivity.
Choose Between Integral or Modular Tools
Small-sized cutting tools are more suitable for integral design. Large-sized machining tools are more suitable for modular design. For large-sized tools, when the tool fails, users often hope to get a new tool by simply replacing small and inexpensive parts. This is especially true for grooving tools and alloy boring tools.
Choose Between Single Cutting Tools or Multi-functional Machining Tools
The smaller the workpiece, the more suitable it is for a multi-functional cutting tool. For example, a multi-functional tool can perform drilling, turning, internal hole processing, thread processing and chamfering. Of course, the more complex the workpiece, the more suitable it is for a multi-functional tool. The machine tool can only bring you benefits when it is cutting, not when it is down.
Choose Between Standard End Mills or Custom Cutting Tools
With the popularity of CNC machining centers, it is generally believed that the shape of the workpiece can be achieved through programming rather than relying on cutting tools. Therefore, non-standard special tools are no longer needed. In fact, today non-standard tools still account for 15% of the total tool sales. Why? The use of special tools can meet the precise workpiece size requirements, reduce processes and shorten the processing cycle. For mass production, non-standard special tools can effectively shorten the processing cycle and reduce costs.
CNC Cutting Tool Chip Control
Remember, your goal is to produce workpieces, not chips, but chips can clearly reflect the cutting status of the tool. In general, people have prejudices about chips because most people have not been trained to interpret chips. Remember the following principle: good chips will not destroy the processing, and bad chips are the opposite.
Inserts are mostly designed with chip breakers, and chip breakers are designed based on feed rates. Whether it is light cutting finishing or heavy cutting roughing.
The smaller the chip, the harder it is to break. For difficult-to-process materials, chip control is a big problem. Although the material being processed cannot be changed. But you can update the tool, adjust the cutting speed, feed rate, cutting depth, tool tip radius, etc. Optimizing chips and optimizing processing is the result of a comprehensive choice.
Cutting Programming
When it comes to tools, workpieces and CNC machines, you often need to define tool paths. Ideally, you will understand basic machine code and have an advanced CAM package. Tool paths must take into account tool characteristics, such as ramping angles, rotation direction, feed and cutting speed. Each tool has a corresponding programming technique to shorten the machining cycle, improve chip removal and reduce cutting forces. A good CAM package can save labor and increase productivity.
Choose Innovative Cutting Tools or Conventional Mature Tools
At the current rate of development of advanced technology, the productivity of cutting tools can double every 10 years. Compared with the recommended tool cutting parameters 10 years ago, you will find that today’s tools can double the processing efficiency, but the cutting power is reduced by 30%. The new tool alloy matrix is stronger and tougher, which can achieve higher cutting speeds and lower cutting forces. The chipbreaker and grade are less application-specific and more versatile.
At the same time, modern tools have added versatility and modularity, which together reduce inventory and expand tool applications. Tool development has also driven new product design and processing concepts. For example, the King Knife and High Feed Milling Cutter, which have both turning and grooving functions, have promoted high-speed machining, minimal lubrication and cooling (MQL) machining and hard turning technology. For these factors and other reasons, you also need to follow the most preferred processing methods and learn about the latest advanced tool technology. Otherwise, there is a risk of falling behind.
CNC Machine Cutting Tools Price
The price of a mill end tool is important, but not as important as the production cost of the tool. Although the tool has its corresponding price, the real value of the tool is the work it performs for productivity. Usually, the lowest-priced tool is the one that causes the highest production cost. The price of the cutting tool accounts for only 3% of the cost of the part. So focus on the productivity of the tool, not its purchase price.
