Friday, December 6, 2019

BEST PARTS CNC Machining || Milling Machine Parts || Roughing

engineers revealed the internal thread processing method of the lathe

There are actually many ways to process internal threads. Today we look at a master who does the internal thread of a tool. It is really amazing. Corresponding to the introduction below, you can easily understand what kind of processing method this is.
Keywork : Tapping Cutting process, Tap Cutting, tap Extrusion ,tapping Turning thread,CNC Machining Maunfacturer ChinaLow-Vloume Manufacturing
Let's share the five main machining methods of internal threads: tapping, extrusion, milling, turning and grinding, and compare their advantages and disadvantages.
1.Tap processing of internal thread

For many thread processing, tapping is an effective and commonly used 

processing method, which usually has the lowest initial cost, but overall it is not necessarily the best economy.
Spiral groove tap adopts variable lead chip flute with 
excellent chip control performance.

Tapping as a continuous cutting process, the workpiece material is sequentially cut by the cutting edges arranged in sequence. The final thread size can be obtained by one pass. Taps are specially produced according to the large, small and medium diameters of the threads. Because the taps must be roughed and finished at the same time as the tool. Therefore, a large amount of chips must be effectively discharged, and excessive pressure may be generated. This can lead to problems with thread quality or damage to the tap.

When tapping, chip control is a big problem that cannot be ignored, especially when processing workpiece materials with low hardness, high viscosity, and easy to produce long chips. These strip-shaped chips may form bird nest-shaped chip clusters around the taps or accumulate in the chip flutes, causing the taps to break in the holes. Aluminum, carbon steel, and 300 series stainless steels are often the most challenging workpiece materials for chip control.

Taps can process almost any workpiece material with a hardness lower than HRC50. Some tool manufacturers provide taps that can even process workpiece materials with hardness up to HRC65.

Pore size is another factor to consider. Most end users can only tap for screw holes with a diameter of less than 16mm. If the hole diameter exceeds 16mm, they will face the question of whether the machine has enough power to rotate the tap. When the diameter of the screw hole is less than 6.35mm, due to the limited chip space and low strength of the small diameter tap, the tapping process is also easy to cause problems.

In addition, the length of the internal thread that a tap can process can usually reach more than three times its diameter. For deep hole threads, taps are often processed faster than single-tooth thread milling cutters. As long as the chips can be successfully discharged out of the hole, tapping can be performed on the screw holes with a depth within the allowable range of the tap design.

Because the diameter and pitch are fixed, a tap cannot process screw holes of different specifications. In addition, since the tap has a large contact area with the hole wall during tapping, a large cutting force is generated. Therefore, the tap may be broken and stuck in the hole, which may cause the workpiece to be scrapped. In order to effectively complete processing, tapping also places high requirements on lubricants.

2.Extrusion molding of internal thread
By transferring (rather than cutting) workpiece material, extrusion taps can machine internal threads up to 4 times the diameter. Since no chips are generated, there is no need to worry about the formation of bird nest-like chips. However, the extruded thread requires that the workpiece hardness be limited to about HRC40 or less. In addition, because the material needs to be transferred, the workpiece material must have good ductility.

The diameter of the extruded tap is usually less than 19mm and can be as small as 0.5mm. The larger the diameter of the tap, the greater the friction generated during machining, and the higher the power requirements of the machine tool.
Compared with cutting taps, extrusion taps have better rigidity and are less likely to break. The pressure acting on the cutting tap is a tangential force through its polygonal surface. The pressure acting on the extrusion tap is a radial force toward the center of the tap, so it is much greater than the tangential force.

Taps can be used for thread extrusion of cast aluminum parts

Compared to cut threads, extruded threads are stronger because the extrusion taps form threads by compressing (rather than cutting) the grain structure of the workpiece material.

Compared with cutting and tapping, extrusion tapping requires a machine tool with greater torque and power, and requires higher workpiece clamping stability. The force required to transfer the workpiece material is greater than that of cutting workpiece material. Extrusion tapping The drilling accuracy requirements for screw holes are also higher.
Extrusion threads are not accepted in some industries, including the medical and aerospace industries. There is a defect in the thread diameter formed by extrusion tapping, and the aerospace industry does not allow sharp points (U-shaped teeth) at the thread diameter. However, this defect does not affect the tensile strength of the thread, so for general-purpose parts, it will not be a reason for rejection.

3.Milling of internal thread
Thread milling cutters use helical interpolation to cut internal and external threads. Most CNC machines produced in the past 10-15 years have thread milling capabilities.
Thread milling can use solid carbide thread milling cutters or indexable insert thread milling cutters (using steel tool holders and carbide inserts). A multi-tooth thread milling cutter can cut a full-depth thread by rotating around a screw hole. A single-tooth thread milling cutter only has a cutting edge on one processing surface, so only one thread can be cut at a time. However, most thread milling cutters have multiple teeth.

Thread milling is suitable for machining workpiece materials with hardness below HRC65, and has excellent versatility. Usually one or two thread milling cutters with different coatings can process a variety of different workpiece materials.

Chip control for thread milling is usually not difficult. Thread milling is an interrupted cut, which means that no matter what the chip characteristics of the workpiece material, broken short chips can be formed.

The thread milling cutter covers a wide range of machining sizes, from threads as small as 0-80 (cutting diameter 1.524mm) to threads with the largest diameter. In general, the optimal hole depth for thread milling cutters should be controlled within about 2.5 times the hole diameter. The cutting force of thread milling is not balanced. If the milling length is too large, the large radial cutting force will cause great lateral pressure, which may cause problems such as deflection of the milling cutter, cutting edge chipping, etc. Broken small cutter.

However, single-tooth thread milling cutters can process deeper screw holes, even screw holes with a depth of up to 20 times the hole diameter. Since all cutting is performed at the end of the milling cutter, there is no problem of tool deflection. There are many users of oilfield equipment or large energy components that require long-handled thread milling cutters. For them, milling multiple threads with a single-tooth milling cutter is slower, but still more cost effective than investing $ 1,000 to buy a 250mm long tap.

Flat-bottomed thread milling cutter for complete threads at the bottom of blind holes

Thread milling has many advantages. A single milling cutter can process a series of screw holes with the same pitch and different apertures, while a single-tooth milling cutter can process screw holes with multiple pitches and multiple apertures. In addition, a thread milling cutter can be used for both blind and through holes, and both right-handed and left-handed threads can be processed. Because the thread milling cutter has a flat bottom structure, a complete thread can be machined near the bottom of the blind hole. Even if the cutter breaks, it is unlikely that the part will be scrapped. Finally, thread milling cutters can be combined with other hole-machining tools into compound tools (such as drilling, chamfering, and thread milling compound tools).

However, compared to tapping, the machining cycle for milling threads is usually longer. Because milling threads requires a special machining program, some users may be reluctant to use this machining method. However, this program is not complicated and can be prepared with many NC programming software.

Some companies still prefer tapping because they don't want operators to intervene in the machining process. Thread milling requires operators to make some compensation adjustments to the machine. The diameter of the milling cutter will gradually decrease due to normal wear. In order to maintain a suitable machining size, the operator must compensate for the amount of tool wear by adjusting. Need to measure the thread tolerance first, and then adjust the processing parameters based on the measured wear amount. The operator can only use a gauge to periodically check the thread. If the test result is unsatisfactory, the tap needs to be replaced.

4. Turning of internal threads
Another way to machine internal threads is to turn the threads with indexable inserts or integral small boring tools on multi-axis machines or lathes. This process can use both single-tooth and multi-tooth blades. Multi-tooth inserts have multiple teeth on each cutting edge, and each subsequent tooth has a deeper cutting depth than the previous one. The use of multi-tooth inserts reduces the number of passes required to complete the thread. However, multi-tooth inserts are more expensive, so they are more advantageous for mass production, but they have no advantage in small batch processing.

Thread turning inserts can process both internal and external threads

Internal threads can also be turned with integral boring tools. When turning a thread with a single-tooth tool, the user can use a full-profile or partial-profile insert (multi-tooth inserts have only full-profile). Footpath). With this type of blade, a separate blade is required for each pitch.

Compared with part-shaped inserts, full-shaped inserts can produce threads with higher strength and accuracy with fewer passes, because the insert can simultaneously process the large, small and medium diameters of the thread.

Some threaded inserts have no thread tips (it cannot cut the small diameter of the thread), and some threaded inserts have only one tooth. Therefore, threads with different pitches can be processed with different cutting depths. This kind of thread has a very sharp arc of the crest, so it will reduce the strength of the coarse thread, and it will take longer to process.

The range of machining sizes for turning threads with indexable tools is wide, from the largest diameter to as small as 6mm. Screw holes with a diameter of less than 6mm need to be processed with solid carbide tools, and the smallest hole diameter that can be processed can reach about 1.25mm. For large-diameter holes, Vargus once machined large screw holes with a diameter of 0.9m on a vertical turret lathe with a service life of about 100 years. There is no other way to machine such large-hole threads except turning. . This older machine does not have helical interpolation.

A thread turning tool with a steel shank is suitable for machining screw holes with a depth of no more than 3 times the hole diameter, while a thread turning tool with a carbide shank can process screw holes with a depth of 4-5 times the diameter.

Vargus's V6 thread turning inserts have a total of 6 cutting angles

Thread turning can also process a variety of workpiece materials, turning threads on workpieces up to HRC50 or high-temperature alloys such as Hastelloy and Inconel alloys. However, due to the high hardness and abrasiveness of these materials, tool life will be shortened.
Chip control is critical in internal thread turning, especially when turning blind hole threads. The user can use the geometry of the blade to control the chip, and use the cross-cut feed method (including radial cross-cut feed, flank cross-cut feed, flank modified cross-cut feed or flank alternate cross-feed) The reverse helix method (the thread formation direction is away from the main axis instead of the main axis) helps chip removal.

Which cross-cut feed method to use depends on the processing conditions, but in most cases, a radial cross-cut feed with modified flanks is beneficial and harmless, so this can be your default preference. However, on almost all machine tools, if a certain parameter in the machining program is not changed, machining will be performed in a radial crosscut feed mode.

5.Grinding of internal threads
Thread grinding is a high-precision machining method, and it is an effective choice for precision internal threads with strict tolerance requirements. Various internal threads, grooves, bearing raceways and other related part features can be machined on the grinder. Typical parts that can be machined with internal thread grinders include threaded ring gauges, roller nuts, ball screws, and more.

Internal thread grinding usually requires a dedicated grinder. Generally speaking, in order to grind a thread with a precise tooth profile, the grinding wheel installation position of the machine tool must be inclined to change according to the spiral angle of the thread, which requires a rotating shaft, which is not available in most general-purpose grinding machines. Sometimes, the A-axis parallel grinding method can also be used, and the multi-toothed grinding wheel that has been modified (corrected its spiral profile) can be directly inserted into the workpiece to grind the external thread. Single tooth grinding wheel.

The internal diameter of thread grinding with better processing economy is usually 10-525mm. The rule of thumb for grinding deep hole internal threads is: the ratio of the length of the grinding wheel shaft to the diameter does not exceed 7: 1. The main challenge in grinding deep hole internal threads is the mutual restriction of the helix angle and the hole diameter. With the increase of the thread length and the decrease of the hole diameter, it is very difficult to grind the workpiece with a large helix angle because the grinding axis is more likely to collide with the workpiece.

Chip control for internal thread grinding involves flushing the grinding zone with coolant. Similarly, because the space of the inner hole is limited, it is quite difficult to make the coolant reach the grinding area in the direction of the rotation of the grinding wheel without preventing the grinding wheel and the grinding shaft from entering the small hole.

The machining accuracy of internal thread grinding is very high, and the grinding wheel can be accurately modified. After the grinding wheel is formed, it can be quickly reshaped as needed. In addition, internal thread grinding can increase productivity. Grinding wheels can be reshaped to process threads of different shapes without having to replace other grinding wheels.

An internal thread grinder with excellent processing performance must have several characteristics: good rigidity and thermal stability, high shafting motion accuracy, precise closed-loop position feedback, and a temperature-controlled precision spindle.
Thread ring gauge for internal thread grinder
How does a part manufacturer determine which internal thread processing method should be used? Each method has its own advantages and disadvantages. If one method does not achieve satisfactory results, it is necessary to try other methods. When determining the internal threading process, it is important to consider what kind of machine tool you have and carefully evaluate tool costs, machining cycles, and tool life.

Contact: Emily
Phone: +86 139 2523 3211
Tel: +86 (0755) 2377 2505
Whatsapp: +86 139 2523 3211
Add: Changshantou Industrial Park, No. 149 QingZhang Road, QingXi Town, DongGuan, China

Thursday, December 5, 2019

Updated the knowledge of bending in sheet metal processing, get it!

Written in front: Bending is a sheet metal processing method. Sheet metal parts of various shapes can be bent to the desired shape after a few passes, which is convenient and fast. Updated the basics about bends, get it.
Keyword tags: CNC Machining Parts, Sheet Metal Processing, Sheet Metal Cutting, Sheet Metal Materials, Wire Drawing, Sheet Metal Cutting, Sheet Metal Bending, Bending Knives
CNC bending process:
The main parameters of the bending machine are: pressure and table length.
1. The main types of bending knives are as follows:
Large Machete Small Machete Sharp Cut Straight Cut Arc Cut
2. The main application bending types of various tools.
(1) Straight knife: It is generally preferred to bend only one bend without considering avoidance.
If the following situations occur, you need to consider avoidance.
As can be seen from the figure, the bending obviously interferes. At this time, another type of bending knife should be considered for bending.

According to the situation on the left side of the picture, a small scimitar is preferred to avoid the situation.
                               In the case of the right side, a sharp knife should be used to avoid the position, but at the same time, it should be noted that the sharp knife has a sharp head, so its strength is poor, so it cannot be used for bending of thick plates. For the plate thickness, no sharp knife is used, but in the process arrangement, think of a method, such as arranging the pressing riveting nut process after bending.
                              In this case, when a small scimitar cannot avoid the position, a large scimitar must be used to avoid the position.
                             Sometimes large scimitars can't be avoided, and you need to increase the process at this time: first press a stamp on the bending line,
For better bending, you can bend the bend to a certain angle first, avoid hitting the knife, and then press the edge to 90 degrees.
In general, the embossing process can be applied to the bending that cannot be completed at one time, so that when the second bending is performed, the bending line can be better shaped according to the original bending printing, otherwise the secondary bending is likely to cause bending deviation. Position or bending angle is not well controlled.

Therefore, we must also consider such problems in the design process, and try to avoid using such a process when the requirements are met, because this does not have the effect of direct bending, and the size and angle may be biased.

The bending machine can also be used to press the work piece to the dead side, first bend the work piece to 30 degrees, and then use a flat knife to press the work piece to death. Generally, the press work side that can be completed with ordinary punches should not be arranged to the press machine because The effect of the dead side is relatively better.
CNC Machining & Sheet Meatl & Brushed 
In addition to interference between the workpiece and the bending knife during the bending process, interference with the bending machine may occur when the size of the workpiece is relatively large.

When we arrange the process, many times we must consider whether it is good to bend or not, because bending is a very important process. Whether the bend is easy to operate directly affects the quality of the bend, and many The quality problems that arise from time to time are due to the failure to control the size of the bend. Therefore, special attention should be paid to the problem of bending during the design process. This is related to the quality stability of the product during mass production.

For different plate thicknesses, its bending size is limited and cannot be too small. Generally, it has a relationship with the lower die. The general principle is: the lower die selects a sipe with a thickness of 6 times the plate thickness. Most in line with experience. The general classification of sipes is divided according to the outer width of the sipes, which are slot 6 and 10 respectively.
At the same time, under some special needs, the supplier will also make special bending knives, but if the shape of the tool is more strange or the degree of curvature is greater, it will inevitably affect the rigidity of the tool and shorten the tool life.
If  you want to prepare for a CNC machining or sheet metal project ? Pls send the 2D or 3D drawing for us. You can get a free quote within 12 hours !!
Contact: Emily
Phone: +86 139 2523 3211
Tel: +86 (0755) 2377 2505
Whatsapp: +86 139 2523 3211
website :
Add: Changshantou Industrial Park,No.149 QingZhang Road, QingXi Town,DongGuan,China 

BEST PARTS mechanical engineers share cutting tool path experience

Tool selection
Here is a summary of BEST PARTS's experience in selecting tools on CNC cutting tools.
Roughing: Under the maximum load of the machine tool, in the most cases of processing, choose the largest knife, the largest amount of feed, as fast as possible, in the case of the same tool The lower feed is inversely proportional to the feed amount. Under normal circumstances, the load of the machine tool is not a problem. The principle of tool selection is mainly based on whether the two-dimensional angle and three-dimensional arc of the product are too small. The principle is that the tool length is greater than the processing depth. For large workpieces, consider whether the chuck can be pushed down, let alone the following.
Light knife purpose: to meet the requirements of workpiece processing: smoothness, flying mold margin, copper male spark level, etc., at the same time, use the largest knife possible, as fast as possible, because the fine knife takes a long time, use the most appropriate advance The cutter and the feed, the larger the lateral feed under the same feed, the faster, the surface feed amount is related to the smoothness after processing, the size of the feed is related to the surface shape of the surface, without hurting the surface, leave The smallest allowance, with the largest knife, the fastest rewinding with appropriate feed.
Clamping method:
1. All the clamps are horizontally long and vertically short;
2. Vise clamping: The clamping height should not be less than 10 mm. The clamping height and processing height must be specified when processing the workpiece. The processing height should be about 5 mm higher than the plane of the vise. The purpose is to ensure robustness. Does not hurt the vise, this kind of clamping is a general clamping, the clamping height is also related to the size of the workpiece, the larger the workpiece, the clamping height will increase accordingly;
3. Plywood clamping: The splint is coded on the workbench, and the workpiece is locked on the splint with screws. This clamping is suitable for workpieces with insufficient clamping height and large processing force, generally large and medium-sized workpieces, and the effect is particularly good. .
4. When the large clamping height of the workpiece is not enough, and it is not allowed to lock the wire at the bottom, use a code iron to clamp. This clamping requires a second clamping. Procedure: a. Good four corners first, and processing other Partially, the four sides are coded at the end, and the four corners are processed. The principle is to be very careful when re-clamping. Do not let the workpiece loose, and then loosen the code first. Large, difficult to deform, soft metals like aluminum and magnesium must use code iron to prevent deformation;
5. Tool clamping: more than 10 mm in diameter, not less than 30 mm; less than 10 mm in diameter, not less than 20 mm,
Note: The impact of the tool on the workpiece can be caused by a, workpiece movement, b, broken tool, c, tool deformation, workpiece damage, d, tool loose, dropped tool or machining workpiece is not allowed
Therefore, the clamping of the tool and the clamping of the workpiece must be firm. Strictly prevent the collision of the cutter and insert the workpiece directly, the classification of the cutter and its scope of application:
1. According to material:
White steel knife: easy to wear, used for copper and small steel
Tungsten steel knife: used for clear angle (especially steel) and light knife.
Alloy knife: similar to tungsten steel knife
Purple knife; used for high-speed cutting, not easy to wear
2. According to the cutter head:
Flat bottom knife: for flat and straight side clearing
Ball Knife: Used for various surface light and light knife
Bull nose knife (single side, double side and five sides): for roughing steel (R0.8, R0.3, R0.5, R0.4)
Coarse leather knife: for roughing, pay attention to the remaining method (0.3)
3, according to the shank: straight bar knife: straight bar knife is suitable for various occasions
Inclined rod knife: but not applicable to straight surfaces and surfaces with an inclination less than that of the rod
4. According to the blades: two blades, three blades, and four blades. The more the number of blades, the better the effect, but the more work, the speed and feed are adjusted accordingly. The more the number of blades is, the longer the life is. :

Ball knife: When the concave ruler is smaller than the ball ruler and the flat ruler is smaller than the ball R, the light is not available (not clear to the bottom corner),
Flying knife: Disadvantages: The concave size and flat ruler are less than the diameter of the flying knife. Advantages: Clear bottom angle. Comparison of the same parameters: V = R * ω, the speed is much faster (flying knife), the force light is bright, the flying knife is mostly used for contour contours, and sometimes the flying knife does not need medium light.
If have any question ,pls send your questions or 3D drawing for free quote !!

Contact: Emily
Phone: +86 139 2523 3211
Tel: +86 (0755) 2377 2505
Whatsapp: +86 139 2523 3211
Add: Changshantou Industrial Park, No. 149 QingZhang Road, QingXi Town, DongGuan, China

Wednesday, November 27, 2019

BEST PARTS provides the injection molding industry

Shenzhen, China, a city with a highly developed economy,
Best's headquarters is located here. Best's development capabilities include CNC machining and injection molding. BEST PARTS develops and produces sophisticated components with high technical requirements in the field of injection molding. We use more than 150 different types of materials and colors. BESTPARTS employees are proud to be committed to the development and production of injection molded products. And engineers are committed to providing solutions with high quality and excellent service.

BESTPARTS is a full-scale plastic injection molded parts manufacturer that provides prototype manufacturing, manufacturing and assembly. With regard to the use of materials, we have the technical knowledge to use the most widely used injection-molded plastic sheet to build the most complex tools.

 Our partners are all over the world. Our unique technology has the ability to produce prototype manufacturing, assembly and value-added services of any size that is difficult. We provide plastic molding services from small to large batches. We have expertise in short-term to large-scale plastic molding. Our areas of focus include:
  • Design and product development
  • High-precision prototyping
  • Machining prototype parts
  • Complex prototyping tools
  • Precision tolerance injection
  • Post-processing capabilities, molding and overmolding
  •  assembly

ISO 9001: 2015 and ISO 13485 certification guarantee our commitment to injection molding quality. Our continuous improvement program includes identifying new technologies, improving manufacturing processes and reducing waste to provide the highest quality injection molded parts.

BEST PARTS has been manufacturing parts for the processing industry. CNC machining, rapid prototyping, die casting, sand casting, manufacturing, rapid tooling, rapid prototyping 3D printing (SLA, SLS), sheet metal processing, vacuum casting, etc. are all services we can offer. We can do efficient rapid prototyping, rapid tooling and rapid production project solutions. BESTPARTS is your one-stop partner for every project. With years of experience, strong team, technology creation and innovation, BEST PARTS has become a competitive enterprise in China.
Contact: Emily
Phone: +86 139 2523 3211
Tel: +86 (0755) 2377 2505
Add: Changshantou Industrial Park,No.149 QingZhang Road, QingXi Town,DongGuan,China 523662