Choosing the best cutting tool is crucial to the success of a machining company. It is also a repetitive task that will directly affect the product processing cycle and the competitiveness of the factory.
Although many people say that we use whatever tools the factory has, if you know how to choose tools, you will be more efficient and save more money. Who else will the boss give a raise to if not you! When choosing cutting tools, you need to consider compatibility with the machine tool and how to process the highest quality parts in the shortest time and at the lowest cost. We will explore how to choose milling tools from the following 15 aspects.
The Most Important Cutting Tool
When any tool stops working, production stops. But not every tool is equally important. The tool that takes the longest to cut has a greater impact on the production cycle, so all else being equal, it should be given more attention. Also, pay attention to tools that process critical parts and have the tightest tolerances. Also, pay attention to tools that have relatively poor chip control, such as drills, grooving cutters, and threading tools. This is because poor chip control can cause downtime.
Matching the Machine
There are right-hand and left-hand tools, so it is important to choose the right one. Generally, right-hand tools are suitable for machines that rotate counterclockwise (CCW) (looking along the spindle). Left-hand tools are suitable for machines that rotate clockwise (CW). If you have several lathes, some with left-hand tools and others that are compatible with both left and right hands, choose left-hand tools. For milling, people usually tend to choose tools that are more versatile.
However, although this type of tool covers a wider range of processing, you will immediately lose the rigidity of the tool, increase the tool flexure deformation, reduce the cutting parameters, and more easily cause processing vibration. In addition, the robot for changing the tool of the machine tool also limits 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 with the Material Being Processed
Carbon steel is the most common material being processed in machining, so most tools are designed based on optimized carbon steel processing. The blade brand needs to be selected according to the material being processed. Tool manufacturers provide a series of tool 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 tool with matching materials.
Milling Tool Specifications
A common mistake is to select a turning tool that is too small and an end mill that is too large. Large turning tools have better rigidity. Large milling cutters are not only more expensive, but also take longer to cut. In general, large tools are more expensive than small tools.
Choose Replaceable Blade or Re-grinding Tools
The principle to follow is simple: try to avoid re-grinding tools. Except for a few drill bits and face milling cutters, try to choose replaceable blade or replaceable head tools when conditions permit. This will save you labor costs while achieving stable processing results.
Tool Materials and Grades
The selection of tool materials and grades is closely related to the performance of the material being processed, the maximum speed and feed rate of the machine tool. Choose a more common tool grade for the group of materials being processed, usually a coated alloy grade.
In actual applications, a common mistake is to try to solve the tool life problem by replacing similar material grades from other tool manufacturers. If your existing 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.
Power Requirements
The guiding principle is to use the machine to its full potential. If you buy a 20hp milling machine, choose the right tools and machining parameters to achieve 80% of the machine’s power, provided the workpiece and fixtures allow. Pay special attention to the power/speed table in the machine’s user manual and choose tools that will achieve the best cutting application based on the effective power range of the machine’s power.
Number of Cutting Tool Edges
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 of 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. And increasing the number of effective cutting edges also directly affects the table feed and productivity.
Choose a Monolithic Tool or a Modular Tool
Small-sized tools are more suitable for monolithic design; large-sized 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 a small and inexpensive part. This is especially true for grooving cutters and boring cutters. If you don’t want to do low-level work, want to get rid of the status quo, and want to learn UG programming, you can find a teacher to learn CNC numerical control technology.
Choose a Single Tool or a Multi-function Tool
The smaller the workpiece, the more suitable the composite tool is. For example, a multifunctional 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 multifunctional tool. The machine tool can only bring you benefits when it is cutting, not when it is stopped.
Choose Standard Cutting Tools or Non-standard Special Cutting Tools
With the popularity of numerically controlled machining centers (CNC), it is generally believed that the shape of the workpiece can be achieved through programming rather than relying on tools. Therefore, special tools are no longer needed. In fact, today, special tools still account for 15% of total tool sales. Why? Using special tools can meet the precise workpiece size requirements, reduce processes and shorten the processing cycle. For large-scale production, special tools can effectively shorten the processing cycle and reduce costs.
Chip Control
Remember that your goal is to machine the workpiece, not the chips, but the chips can clearly reflect the cutting state of the tool. In general, people have prejudices about chips because most people have not been trained to interpret chips. Remember the following principles: good chips do not destroy the processing, and bad chips do the opposite. Most inserts are 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. Chip control is a big problem for difficult-to-machine materials. Although the material being processed cannot be changed, the tool can be updated, and the cutting speed, feed rate, cutting depth, tool tip radius, etc. can be adjusted. Optimizing chips and optimizing processing is the result of a comprehensive selection.
Programming
When facing tools, workpieces and CNC machining machines, it is often necessary to define tool paths. Ideally, you should understand basic machine codes and have advanced CAM programming software. Tool paths must take into account tool characteristics such as ramping angle, rotation direction, feed, cutting speed, etc. Each tool has corresponding programming technology to shorten the processing cycle, improve chips, and reduce cutting forces. Good CAM programming software can save labor and improve productivity.
Choose Innovative Tools or Conventional Mature Tools
At the current rate of development of advanced technology, the productivity of cutting tools can double every 10 years. Compare the cutting parameters recommended for tools 10 years ago and you will find that today’s tools can double the processing efficiency while reducing cutting power by 30%. The new tool alloy matrix is stronger and tougher, which can achieve higher cutting speeds and lower cutting forces. The chip breaker and grade are less application-specific and more versatile.
At the same time, modern tools have increased versatility and modularity, which together reduce inventory and expand tool applications. Tool development has also driven new product design and processing concepts, such as the King Knife, which combines turning and grooving functions, and high-feed milling cutters, which have promoted high-speed machining, minimal lubrication and cooling (MQL) machining, and hard turning technology. For these and other reasons, you also need to keep up with the most preferred processing methods and learn about the latest advanced tool technology, otherwise you are in danger of falling behind.
Cutting Tool Price
The price of the tool is important, but it is not as important as the production cost paid for the tool. Although the tool has its corresponding price, the real value of the tool lies in the role it performs for production efficiency. Usually, the lowest-priced tool is the one that causes the highest production cost. The price of cutting tools accounts for only 3% of the cost of the part. So please focus on the productivity of the tool, not its purchase price. Machining is developing into a professional science, but experience is still irreplaceable. As a feedback to customers, tool suppliers’ services are free, and they can even provide free tool test cutting. Experienced experts from tool suppliers can provide users with the best and guiding help in choosing tools.
