With the increasingly updated processing technology, CNC machining has also undergone a lot of changes. Many experts pointed out that in the future, CNC will be the mainstream processing mode. In the CNC machining process, the tool is the most important, today, we will understand the CNC tool in detail.




CNC machining tool concept



A tool is a tool used for cutting in mechanical manufacturing. Generalized cutting tools include both cutting tools and abrasive tools. The vast majority of knives are used for machines, but there are also hand tools. Since the tools used in mechanical manufacturing are basically used to cut metal materials, the term "tool" is generally understood as a metal cutting tool. The cutting tools used for cutting wood are called woodworking tools.


CNC machining tool



Tool classification

Cutting tools can be divided into five categories according to the form of the workpiece machined surface.

Cutting tools for processing various outer surfaces, including cutting tools for processing various outer surfaces, including turning tools, planing knives, milling cutters, outer surface broach and file, etc.

Hole processing tools, including drill, reaming drill, boring cutter, milling cutter and internal surface broach, etc.

Thread processing tools, including tap, die, automatic opening thread cutting head, thread turning tool and thread milling cutter.

Gear processing tools, including hob, gear shaper cutter, shaving cutter, bevel gear processing tool, etc.

Cutting tools, including inserted circular saw blade, band saw, bow saw, cutting tool and saw blade milling cutter, etc.

In addition, there are combination tools.


Hole cutting tool



Tool structure

The structure of various tools is composed of a clamping part and a working part. The clamping part and working part of the overall structure of the tool are done on the tool body; The working part of the tool (the tooth or blade) is mounted on the tool body.

The clamping part of the tool has two kinds of holes and handles. The tool with hole relies on the inner hole set on the spindle or mandrel of the machine tool, and transmits the torsional torque with the help of the axial key or the end key, such as the cylindrical milling cutter and the sleeve face milling cutter.

The tool with the handle is usually rectangular handle, cylindrical handle and conical handle three kinds. Turning tools, planing tools, etc. are generally rectangular handles; The conical handle withstands the axial thrust with the taper and transmits the torque with the help of friction. Cylindrical shank is generally suitable for smaller twist drill, end mill and other tools, cutting with the help of the friction generated when clamping torque transfer. The shank of many tools with handles is made of low alloy steel, and the working part is made of high speed steel welded to each other.



The basic properties that the tool material should have

1. High hardness

The hardness of the tool material must be higher than the hardness of the workpiece material to be machined, which is the basic feature that the tool material should have.

2. Sufficient strength and toughness

The material of the cutting part of the tool must withstand great cutting force and impact force when cutting. The bending strength and impact toughness reflect the ability of tool material to resist brittle fracture and edge breakage.

3. High wear resistance and heat resistance

The wear resistance of tool materials refers to the ability to resist wear. The higher the hardness of the tool material, the better the wear resistance; The higher the high temperature hardness, the better the heat resistance, the tool material at high temperature resistance to plastic deformation, anti-wear ability is also stronger.

4. Good thermal conductivity

Large thermal conductivity means good thermal conductivity, and the heat capacity generated during cutting is easily transmitted out, thereby reducing the temperature of the cutting part and reducing tool wear.

5. Good technology and economy

In order to facilitate manufacturing, the tool material is required to have good machinability, including forging, welding, cutting, heat treatment, grindability and so on. Economy is one of the important indexes to evaluate and promote the application of new tool materials.

6. Resistance to bonding

Prevent the workpiece and the tool material molecules under the action of high temperature and high pressure adsorption bond.

7. Chemical stability

It means that the tool material is not easy to react chemically with the surrounding medium at high temperature.

Tool coating

Aluminum alloy indexable inserts are now coated with hard or composite layers of titanium carbide, titanium nitride, alumina by chemical vapor deposition. The physical vapor deposition method that is being developed can be used not only for aluminum alloy tools, but also for high-speed steel tools such as drills, hobs, taps and milling cutters. As a barrier that prevents chemical diffusion and heat conduction, the hard coating slows down the wear rate of the tool during cutting, and the life of the coated blade is about 1 to 3 times higher than that of the uncoated blade.




How to choose a tool



Tool selection is carried out in the human-machine interaction state of NC programming. The tool and handle should be correctly selected according to the machining capacity of the machine tool, the performance of the workpiece material, the processing procedure, the cutting amount and other relevant factors.

The general principle of tool selection: easy installation and adjustment, good rigidity, high durability and accuracy. On the premise of meeting the processing requirements, try to choose a shorter tool handle to improve the rigidity of the tool processing. When selecting the tool, the size of the tool should be adapted to the surface size of the workpiece to be machined.

1. End milling cutter is often used to process the peripheral outline of plane parts.

2. When milling the plane, carbide blade milling cutter should be selected.

3. When processing convex and grooves, choose high-speed steel end milling cutter.

4. When processing the blank surface or roughing the hole, you can choose the corn milling cutter with cemented carbide blade.

5. For the processing of some vertical surface and variable bevel contour, ball end milling cutter, ring milling cutter, conical milling cutter and disk milling cutter are often used.

6. In the processing of free-form surface, because the cutting speed of the end of the ball head tool is zero, so in order to ensure the processing accuracy, the cutting line spacing is generally very dense, so the ball head is often used in the finishing of the surface.

7, flat head tool in the surface processing quality and cutting efficiency are better than the ball head knife, therefore, as long as the premise of ensuring but cutting, whether it is rough surface machining or finishing, should be preferred to choose flat head knife.

8. In the machining center, various tools are installed on the tool library, and the tool selection and tool change are carried out at any time according to the procedure. Therefore, the standard tool handle must be used in order to make the standard tool for drilling, boring, expanding, milling and other processes quickly and accurately installed on the machine spindle or tool library. The number of tools should be reduced as far as possible; After a tool is installed, it should complete all the processing parts that it can carry out; Rough finishing tools should be used separately, even if the same size specifications of the tool; Milling before drilling; Surface finishing is carried out first, and then 2D contour finishing is carried out. Where possible, the automatic tool change function of CNC machine tools should be used as much as possible to improve production efficiency.


Problems encountered in processing aluminum and solutions



Problems encountered in processing aluminum and solutions when processing pure aluminum, easy to stick knife analysis and solutions:

1. Aluminum material is soft in texture and easy to stick at high temperature;

2. Aluminum is not resistant to high temperature, easy to open;

3. Related to processing cutting fluid: good oil lubrication performance; Good water-soluble cooling performance; High dry cutting cost;

4. When processing pure aluminum, the end mill dedicated to aluminum processing should be selected: positive front Angle, sharp cutting edge, large chip discharge slot, 45 degrees or 55 degrees helix Angle;

5. The material of the workpiece and the CNC tool has a greater affinity.

6. Rough front tool processing soft materials.

Recommendation: Machine tool conditions are poor to good requirements are low to high, please use high-speed steel, coated polished carbide, PCD polycrystalline diamond and single crystal diamond.

7. Low speed can be avoided by cutting fluid, high speed oil mist lubrication, the effect can be improved, aluminum alloy suitable


Tool future development direction



Due to the high temperature, high pressure, high speed, and the parts working in the corrosive fluid medium, the application of difficult to process more and more materials, the automation level of cutting processing and the processing accuracy requirements are getting higher and higher. In order to adapt to this situation, the development direction of the tool will be the development and application of new tool materials; Further develop the vapor deposition coating technology of the tool, and deposit higher hardness coating on the matrix of high toughness and high strength, so as to better solve the contradiction between hardness and strength of the tool material; Further development of indexable tool structure; Improve the manufacturing accuracy of the tool, reduce the difference in product quality, and optimize the use of the tool.How to choose CNC aluminum alloy machining tool.

Thread machining is one of the very important applications of CNC machining center. The machining quality and efficiency of thread will directly affect the machining quality of parts and the production efficiency of machining center.With the improvement of the performance of CNC machining center and the improvement of cutting tools, the method of thread machining is also improving, and the accuracy and efficiency of thread machining are also gradually improving. In order to enable technicians to reasonably select thread processing methods in processing, improve production efficiency and avoid quality accidents, several thread processing methods commonly used in CNC machining center are summarized as follows:1. Tap processing method


1.1 classification and characteristics of tap processingUsing tap to process threaded hole is the most commonly used processing method. It is mainly applicable to threaded holes with small diameter (d30) and low requirements for hole position accuracy.
In the 1980s, the flexible tapping method was adopted for threaded holes, that is, the flexible tapping collet was used to clamp the tap. The tapping collet can be used for axial compensation to compensate the feed error caused by the non synchronization between the axial feed of the machine tool and the spindle speed, so as to ensure the correct pitch. The flexible tapping collet has complex structure, high cost, easy damage and low processing efficiency. In recent years, the performance of CNC machining center Gradually, the rigid tapping function has become the basic configuration of CNC machining center.
Therefore, rigid tapping has become the main method of thread machining.That is, the tap is clamped with a rigid spring collet, and the feed of the spindle is consistent with the spindle speed controlled by the machine tool.Compared with the flexible tapping chuck, the spring chuck has the advantages of simple structure, low price and wide application. In addition to holding the tap, it can also hold the end milling cutter, drill bit and other tools, which can reduce the tool cost. At the same time, the rigid tapping can be used for high-speed cutting, improve the use efficiency of the processing center and reduce the manufacturing cost.
1.2 determination of threaded bottom hole before tappingThe processing of threaded bottom hole has a great impact on the life of tap and the quality of thread processing. Generally, the diameter of threaded bottom hole drill is close to the upper limit of the diameter tolerance of threaded bottom hole,For example, the bottom hole diameter of M8 threaded hole is 6.7 0.27mm, select the drill bit diameter as 6.9mm. In this way, the machining allowance of tap can be reduced, the load of tap can be reduced, and the service life of tap can be improved.
1.3 selection of tapWhen selecting taps, first of all, the corresponding taps must be selected according to the processed materials. The tool company produces different types of taps according to different processing materials, and special attention should be paid to the selection.
Because the tap is very sensitive to the processed materials compared with the milling cutter and boring cutter. For example, using the tap for processing cast iron to process aluminum parts is easy to cause thread dropping, disorderly threading and even tap breaking, resulting in workpiece scrapping. Secondly, pay attention to the difference between the through-hole tap and the blind hole tap. The front-end guide of the through-hole tap is long, and the chip removal is the front-end chip. The front-end guide of the blind hole is short, and the chip removal is the front-end It is the back chip. Machining the blind hole with a through-hole tap cannot guarantee the thread machining depth. Moreover, if a flexible tapping collet is used, it should also be noted that the diameter of the tap handle and the width of the four sides should be the same as that of the tapping collet; the diameter of the tap handle for rigid tapping should be the same as that of the spring jacket. In short, only a reasonable selection of the tap can ensure the smooth machining.
1.4 NC programming of tap machiningThe programming of tap machining is relatively simple. Now the machining center generally solidifies the tapping subroutine and only needs to assign values to various parameters. However, it should be noted that the meaning of some parameters is different due to different NC systems and different subroutine formats.For example, the programming format of Siemens 840C control system is g84 x_y_r2_r3_r4_r5_r6_r7_r8_r9_r10_r13_. Only these 12 parameters need to be assigned during programming.
2. Thread milling method2.1 characteristics of thread millingThread milling adopts thread milling tool and three-axis linkage of machining center, that is, x-axis and y-axis arc interpolation and z-axis linear feed.
Thread milling is mainly used to process large hole threads and threaded holes of difficult to process materials. It mainly has the following characteristics:(1) high processing speed, high efficiency and high processing precision. The tool material is generally cemented carbide, with fast tool walking speed. The manufacturing precision of the tool is high, so the milling thread precision is high.(2) the milling tool has a wide range of application. As long as the pitch is the same, whether it is left-hand thread or right-hand thread, one tool can be used, which is conducive to reducing the tool cost.
(3) milling is easy to remove chips and cool, and the cutting condition is better than that of tap. It is especially suitable for thread processing of difficult to process materials such as aluminum, copper and stainless steel, especially for thread processing of large parts and components of precious materials, which can ensure the thread processing quality and workpiece safety.(4) because there is no tool front-end guide, it is suitable for machining blind holes with short thread bottom holes and holes without tool return grooves.2.2 classification of thread milling tools
Thread milling tools can be divided into two types, one is the machine clamp cemented carbide blade milling cutter, and the other is the integral cemented carbide milling cutter. The machine clamp cutter has a wide range of applications. It can process holes with thread depth less than the blade length or holes with thread depth greater than the blade length. The integral cemented carbide milling cutter is generally used to process holes with thread depth less than the tool length.2.3 NC programming of thread millingThe programming of thread milling tool is different from that of other tools. If the processing program is wrong, it is easy to cause tool damage or thread processing error. The following points should be paid attention to during programming:
(1) firstly, the threaded bottom hole shall be processed well, the small diameter hole shall be processed with a drill, and the larger hole shall be bored to ensure the accuracy of the threaded bottom hole.(2) when cutting in and cutting out the tool, the arc path shall be adopted, usually 1 / 2 turn, and 1 / 2 pitch shall be traveled in the z-axis direction to ensure the thread shape. The tool radius compensation value shall be brought in at this time.(3) the x-axis and y-axis circular arc shall be interpolated for one week, and the main shaft shall travel a pitch along the z-axis direction, otherwise the threads will be buckled disorderly.
(4) specific example program: the diameter of thread milling cutter is 16. The threaded hole is M48 1.5, the depth of threaded hole is 14.The processing procedure is as follows:(the procedure of threaded bottom hole is omitted, and the bottom hole shall be bored) G0 G90 g54 x0 y0g0 Z10 m3 s1400 m8g0 z-14.75 feed to the deepest thread G01 G41 x-16 Y0 F2000 move to the feed position, add radius compensation G03 x24 Y0 z-14 I20 J0 f500 cut in with 1 / 2 circle of arc G03 x24 Y0 Z0 I-24 J0 F400 cut the whole thread G03 x-16 Y0 z0.75 I-20 J0 f500 cut out with 1 / 2 circle of arc G01 G40 x0 Y0 return to the center and cancel radius compensation G0 Z100M30
3. Snap method3.1 characteristics of snap methodLarge threaded holes can sometimes be encountered on box parts. In the absence of tap and thread milling cutter, the method similar to lathe pick-up can be adopted.
Install the thread turning tool on the boring bar to bore the thread.The company once processed a batch of parts with m52x1.5 thread and 0.1mm positional degree (see Figure 1). Because of the high positional requirements and large thread hole, it is impossible to process with tap and there is no thread milling cutter. After the test, the thread picking method is adopted to ensure the processing requirements.3.2 precautions for buckle picking method
(1) after the spindle is started, there shall be a delay time to ensure that the spindle reaches the rated speed.(2) during tool retraction, if it is a hand ground thread tool, because the tool cannot be grinded symmetrically, reverse tool retraction cannot be adopted. The spindle orientation must be adopted, the tool moves radially, and then the tool retraction.(3) the manufacturing of the cutter bar must be accurate, especially the position of the cutter slot must be consistent. If it is inconsistent, multiple cutter bars cannot be used for processing, otherwise it will cause disorderly buckle.
(4) even if it is a very fine buckle, it cannot be picked with one knife, otherwise it will cause tooth loss and poor surface roughness. At least two knives shall be divided.(5) the processing efficiency is low, which is only applicable to single piece, small batch, special pitch thread and no corresponding tool.3.3 specific procedures
N5 G90 G54 G0 X0 Y0N10 Z15N15 S100 M3 M8
N20 G04 X5 delay to make the spindle reach the rated speedN25 G33 z-50 K1.5 turnbuckleN30 M19 spindle orientation
N35 G0 X-2 cutterN40 G0 z15 tool retractionEditing: JQ

1 Tool change of hat type magazineThe fixed address tool change mode is mostly adopted, and the tool number is fixed corresponding to the tool seat number. The tool change action is realized by the lateral movement of the tool magazine and the up and down movement of the spindle, which is referred to as the spindle tool change mode for short. Because it has no tool change manipulator, the tool selection action cannot be preselected before the tool change action. The tool change instruction and tool selection instruction are generally written in the same program segment, and the instruction format is as follows:M06 T


When the command is executed, the tool magazine first turns the tool holder corresponding to the tool number on the spindle to the tool change position, and switches the tool on the spindle back to the tool holder, and then the tool magazine turns the tool specified in the command to the tool change position and changes the spindle.For this tool magazine, even if TX x is executed before M06, the tool cannot be preselected, * the action of final tool selection is still executed when M06 is executed. If there is no TX X in front of M06, the system will give an alarm.2 Tool change of disc and chain magazine
Most of them use random address tool change mode. The corresponding relationship between tool number and tool seat number is random, but its corresponding relationship can be remembered by NC system. The tool change of this tool magazine depends on the manipulator. The action of the command and tool change is: the tool command TX controls the rotation of the tool magazine and turns the selected tool to the tool change working position, while the tool change command M06 controls the action of the tool change manipulator to realize the tool exchange between the spindle tool and the tool change position of the tool magazine. The tool selection command and tool change command can be in the same program segment or written separately. The actions corresponding to tool selection and tool change command can also be operated simultaneously or separately. The instruction format is as follows:
Tx x M06;When the command is executed, the tool magazine first turns the TX tool to the tool change position, and then the manipulator exchanges the tool of the tool magazine with the tool of the spindle to realize the purpose of changing the TX tool to the spindle.After reading the above two methods, it can be seen that method 2 overlaps the tool selection action with the machining action, so that when changing the tool, it is not necessary to select the tool and change the tool directly, which improves the work efficiency.
As mentioned earlier, the tool change command of the tool magazine is related to the machine tool manufacturer. For example, some tool magazines require that not only the Z axis must return to the tool change point, but also the Y axis must return to the tool change point. The program format is as follows:
When writing the instructions of tool selection and tool change in the same program section, the execution rules of tools from different manufacturers may also be different. If any, regardless of the writing order, the rules of tool selection and tool change shall be followed. Some rules stipulate that the tool selection command must be written before the tool change command is executed. Otherwise, the action is to change the tool first and then select the tool, as shown in the above program. In this case, if the tool selection command is not written before the M06 command is executed, the system will give an alarm.

Brand of moisture meter: Boshi Model: bos-180a series Test item: automotive plastic sheet


The water content of plastics is a key reason affecting the production process, commodity appearance and commodity characteristics of resin materials such as polyethylene (PE) and polypropylene (PP). In the injection molding process, if the plastic raw materials with excessive water content are used for production and manufacturing, it will cause some production and processing problems and affect the product quality, such as cracking of the surface layer, reflection, wear resistance, reduction of material mechanical properties such as service performance and tensile strength, etc. Therefore, the control of water content is particularly important for the production of high-quality plastic products.
Testing water content is a necessary step in the production of plastic materials. Testing moisture content is basically divided into national standard method and rapid moisture tester method. Boshi plastic rapid moisture tester is a widely used instrument and equipment at present.(auto plastic parts)Test steps:
1. First, take out the moisture meter, place it and power it on, then break the test material into small pieces, pour out about 6 grams of plastic pieces and pour them into the stainless steel tray. In order to dry and dry the plastic thoroughly during the test, we spread the fine pieces of plastic parts into a scattered form so that the temperature can penetrate into the plastic parts. Use tweezers to lay small pieces of plastic parts evenly. In order to avoid the zoom and blackening of small pieces of plastic parts after baking, we set the temperature at 105 , press the "start" key to start the test for 1 minute and 49 seconds, and then the test ends, and the test data displays 0.3%;
2. In order to obtain more stable data results, wait for the moisture meter of plastic parts to cool down before the second test. When the temperature of the instrument itself drops below 40 , also take about 6 grams of small pieces of plastic parts into the stainless steel tray, and lay the small pieces of plastic parts evenly. This time, we set the temperature at 105 , press the "start" key to start the test, and the test ends after 1 minute and 38 seconds, The test data showed 0.29%;Test data:From the above tests, we found that the moisture of these plastic sheets was well controlled and the moisture distribution was relatively uniform, which promoted the plastic parts to be completely dry after the test, and the moisture data results were also very good.
matters needing attention:1. Small pieces of plastic sheets shall be small enough to ensure the complete drying of water in plastic parts, and shall be evenly spread on the tray as far as possible, rather than simply stacked together.2. Do not set the temperature too high to prevent the plastic parts from melting in case of high temperature. The moisture meter of plastic parts has its use environmental restrictions. Please use it under the environmental conditions specified in the product operation manual. Do not operate in harsh environments.
3. As the instrument is a precision instrument, do not knock the workbench or vibrate the instrument during heating, otherwise the measurement will be inaccurate.4. After the test, do not touch the tray for the Yi first time to avoid scalding.Editing: JQ

CNC machining process common problem points and improvement methods

Starting from the actual production, this paper summarizes the common problems and improvement ways of CNC machining process, and how to choose the three important factors of speed, feed rate and cutting depth in different application fields

The workpiece is over-cut
The reason:


Knife, tool strength is not enough too long or too small, resulting in knife.
Improper operation by the operator.
Uneven cutting allowance (such as: 0.5 on the side of the surface, 0.15 on the bottom)
Improper cutting parameters (such as: tolerance is too large, SF setting too fast, etc.)

Improvements:


The principle of using a knife: can be big or small, can be short or not long.
Add the clearing procedure, and the margin is as even as possible (the margin on the side and the bottom is the same).
Reasonable adjustment of cutting parameters, large margin corner round.
With the SF function of the machine, the operator fine-tunes the speed to achieve the best cutting effect.

The central question
The reason:


Operator manual operation is not accurate.
There are burrs around the mold.
The center bar has magnetic field.
The four sides of the mold are not vertical.

Improvements:


Manual operation should be carefully checked repeatedly, and the points should be at the same point and height as far as possible.
Remove burrs with a whetstone or file around the mold, wipe clean with a rag, and finally confirm with your hand.
Demagnetize the dividing rod before dividing the mold (ceramic dividing rod or other).
Check whether the four sides of the mold are vertical (if the verticality error is large, it is necessary to review the plan with the fitter).

The knife problem
The reason:


Operator manual operation is not accurate.
Tool clamping error.
The blade on the knife is wrong (the knife itself has a certain error).
There is an error between R knife and flat knife and flying knife.

Improvements:


Manual operation should be carefully checked repeatedly, and the knife should be at the same point as possible.
Blow clean with air gun or wipe clean with rag when clamping the tool.
One blade can be used when the blade on the flying knife is to measure the rod and light the bottom surface.
A separate knife program can avoid the error between R knife flat knife flying knife.

The crash - programming
The reason:


The safety height is not enough or not set (the knife or chuck hits the workpiece when the fast feed G00).
The tool on the program list and the actual program tool are written wrong.
The tool length (blade length) and the actual machining depth on the program list are wrong.
The depth Z-axis fetch number and the actual Z-axis fetch number on the program are written incorrectly.
The coordinates are set incorrectly during programming.

Improvements:


Accurate measurement of the height of the workpiece also ensures that the safety height is above the workpiece.
The tool on the program list should be consistent with the actual program tool (try to use the automatic program list or use the picture program list).
Measure the actual depth of machining on the workpiece, write the length of the tool and the length of the blade on the program sheet (generally, the tool clip length is 2-3MM higher than the workpiece, and the blade length avoidance is 0.5-1.0MM).
Take the actual Z-axis number on the workpiece and write it clearly on the program sheet. (This operation is generally written manually to check repeatedly).

Crash machine - Operator
The reason:


Depth Z-axis alignment error ·
The number of touch and operation errors (such as: unilateral access without feed radius, etc.).
Use the wrong knife (such as: D4 knife with D10 knife to process).
The program goes wrong (for example: A7.NC goes A9.NC).
The hand wheel is rotated in the wrong direction during manual operation.
Press the wrong direction (for example, -X +X) during manual fast feed.

Improvements:


Depth Z-axis knife must pay attention to the position of the knife. (bottom, top, analysis, etc.).
Check the number of touch and operation repeatedly after completion.
When installing the tool, it should be installed after repeated check with the program list and the program.
The program should go one by one in order.
In the manual operation, the operator should strengthen the operation proficiency of the machine tool.
In the manual fast movement, you can first raise the Z axis to the workpiece above the move.

Surface accuracy
The reason:


The cutting parameters are unreasonable and the workpiece surface is rough.
The edge of the tool is not sharp.
The tool clamping is too long, and the blade is too long.
Chip removal, air blowing, oil flushing is not good.
Programming cutting mode, (you can try to consider going down milling).
The workpiece has burrs.

Improvements:


Cutting parameters, tolerances, allowance, speed feed Settings should be reasonable.
The tool requires the operator to check and replace it periodically.
When installing the tool, the operator is required to clip as short as possible, and the blade should not be too long.
For the lower cut of flat knife, R knife and round nose knife, the speed feed setting should be reasonable.
The workpiece has burrs: the root of our machine tools, tools, and cutting methods are directly related. Therefore, we need to understand the performance of the machine tool and repair the edge with burrs.

The blade is broken
Reasons and improvements:

1. Feed too fast

-- Slow down to a suitable feed speed

2. Feed too fast at the beginning of cutting

-- Slow down the feed rate at the beginning of cutting

3. Clamp loosely (knife)

-- Clamp

4. Clamping loose (workpiece)

-- Clamp

5. Insufficient rigidity (tool)

-- Use the shortest knife allowed, a little deeper in the grip, and try downmilling

6. The cutting edge of the tool is too sharp

- Change the fragile cutting edge Angle, one edge

7. Insufficient rigidity of machine tools and tool handles

-- Use a rigid machine tool and a tool handle

Wear and Tear
Reasons and improvements:

1. Machine speed is too fast

- Slow down and add enough coolant

2. Harden the material

-- Use advanced tools and tool materials to increase surface treatment

3. Chip adhesion

- Change the feed speed, chip size or clean the chip with cooling oil or air gun

4. Improper feed speed (too low)

-- Increase feed speed and try downmilling

5. The cutting Angle is not suitable

- Change to the appropriate cutting Angle

6. The first back corner of the knife is too small

-- Change to a larger back Angle

Destruction
Reasons and improvements:

1. Feed too fast

-- Slow down the feed rate

2. The cutting amount is too large

-- Use smaller cutting amounts per edge

3. Blade length and full length are too large

- Deep grip, with a short knife, try to mill down

4. Too much wear and tear

-- Regrind at an early stage

Vibration marks
Reasons and improvements:

1. Feed and cutting speed is too fast

- Correct feed and cutting speed

2. Insufficient rigidity (machine tools and tool handles)

- Use better machine tools and tool handles or change the cutting conditions

3. The rear Angle is too large

- Change to a smaller back Angle, machining the edge belt (oil stone grinding once)

4. Clamp loosely

-- Clamp the workpiece

◆ Consider speed, feed

The relationship between the three factors of speed, feed and cutting depth is the most important factor to determine the cutting effect, inappropriate feed and speed often lead to reduced production, poor workpiece quality, tool damage.

Use the low speed range for:


High hardness material
Headstrong big material
Hard to cut material
Heavy cut
Minimal tool wear
Maximum tool life

Use the high speed range for:


Soft material
Good surface quality
Smaller tool diameter
Light cut
Large brittle workpiece
Manual operation
Maximum processing efficiency
Non-metallic material

Use high feeds for:


Heavy, rough cutting
Rigid construction
Machinable material
Roughing tool
Surface cutting
Low tensile strength material
Coarse tooth milling cutter

Use a low feed for:


Light machining, fine cutting
Brittle structure
Difficult material
Small cutter
Deep vertical groove machining
High tensile strength material
Finishing tool

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