chengcg – Page 126 – CNC Machining & Turning, Milling, Metal parts

Conditions for precision milling of gantry

Gantry milling processing and milling fill the gap that carving milling machine can’t process large-scale mold in the current market. The machine has the advantages of average transmission, high rigidity, heavy body and large processing size, which can meet the requirements of carving and milling of most large molds in the market at present.

The tool path of gantry milling must be in accordance with the following strategies:

1. High speed machining should be based on down milling to reduce tool wear and improve machining accuracy.

According to the principle of shallow cutting and small layer depth, the correct layering route is selected to complete the correct intelligence of machining and the stability of load.

3 arc cutting should be added at the corner to prevent the sudden change of velocity vector target and the sharp change of tool load.

4 in the plane two-way cutting, it is possible to add arc transition between two adjacent tool paths, so as to make the tool move smoothly laterally. In the process of two-way cutting in space, it is advisable to select several extended transition modes, such as space circular arc cutter, space inner circular arc cutter, space outer circular arc cutter and “Golf” type transition cutter, which not only ensures the smoothness of cutter path, but also effectively prevents the phenomenon of turning and hard bending between two lines. This transition mode is widely used in high-speed milling of various curved surfaces.

5 to prevent the normal direction direct feed and retreat on the appearance, the spiral, arc and diagonal mode should be selected to ensure smooth feed and retreat.

In order to prevent the sharp change of the cutting load, the different ways are used to separate the steep wall and the non steep wall, which can increase the cutting speed and average the surface roughness of the parts.

Gantry milling processing conditions:

● prevent sharp changes in tool movement.

● prevent feeding and withdrawing on the appearance. Sink directly to the next depth in appearance milling. If it can’t sink directly, it can sink through spiral or slope.

● the infeed (Fz) of each tooth shall be equal to (AE).

● real cutting roughness milling is selected for gantry milling – the step distance is calculated by the roughness of the tool.

● the best surface machining quality can be achieved when the feed rate of each tooth is constant.

Do you understand the above Longmen milling content? If you have any other questions, please call us for consultation. We will sincerely serve for you

How to model and simulate the parts of automobile inspection tools

When the existing testing equipment of automobile parts in stamping or injection molding can not meet the requirements of testing, it needs to use the inspection tool accessories. However, when planning reflection, it is necessary to analyze the part products of the inspection tool accessories, check whether the 3D digital model of the product is the same as the 2D drawing of the product. The original data of the 3D digital model of the product is the entity, still the piece. The following two points are for the entity or What are the differences in the design process of the inspection tool for the slice.

1、 When the original data of 3D digital analog of automobile product is entity (i.e. the product already has thickness), it is better to use the datum plane (or lap plane) of the product as an offset datum, or the datum plane marked on the GD & T drawing of the product as the offset plane. In the design of imitation block, there are not many phenomena of target selection, which are usually well mastered.

2、 When the original data of 3D digital analog of automobile product is a piece (i.e. the product is a surface without thickness), the target of product thickness must be studied. Once the thickness target is definitely wrong, or there is no target to study the thickness, the product can not be put into the inspection tool for detection, resulting in the scrap of the imitation block of the inspection tool accessories.

Therefore, in the process of the design of checking tool parts, it is very important to analyze the product of automobile parts, especially when the original data of the product is a piece, it should be very concerned.

Problems in the design of fixture parts

The design of fixture parts is usually simple in structure, which makes people feel that the structure is not very complex. The more we find that the hydraulic fixture is widely used, which greatly simplifies the original mechanical structure. However, if we do not make a detailed study in the design process, there will inevitably be unnecessary difficulties:

1 blank allowance of the workpiece to be processed. The size of forming blank is too large, and interference occurs. So we must plan the rough drawing before design. Leave plenty of space.

2. Smooth chip removal of fixture accessories. Due to the limited machining space of the machine tool, the fixture is often designed in a compact space. At this time, it is often ignored that the iron chips accumulated in the dead corner of the fixture during the machining process, including the unsmooth outflow of chip liquid, which brings many difficulties to the later machining. Therefore, at the beginning of essence, we should study the problems in the process of machining. After all, the fixture will increase efficiency and be easy to operate.

3. Overall opening of fixture. Ignoring the opening, the manipulator is difficult to install, time-consuming and laborious, and the design is taboo.

4. Basic comment principle of fixture accessory design. Each set of fixture has to go through many times of clamping and loosening, so it may reach the user’s requirements at the beginning, but the fixture should have its accuracy maintenance, so do not design some equipment that is against the truth. Even if you are lucky now, it will not last forever. A good design should be tempered by time.

5. Interchangeability of positioning elements. It is important to wear the positioning elements, so it is necessary to study the quick and simple replacement. Do not design as larger parts.

The accumulation of fixture design experience is very important. Occasionally design is one thing, and in essence use is another. So good design is a process of accumulation and summary. The above content is introduced here first, you are interested, please pay more attention to us, and will bring you different knowledge at any time.

Characteristics of precision parts processing

Five axis linkage machining center is a machining center with high technology content and high weekly density, which is specially used to process complex curved surface. This machining center system has full weight lifting influence on aviation, sail sea, military, scientific research, sophisticated equipment, high-precision medical equipment and other industries in a country.

1、 What is a five axis machining center

Five axis linkage machining has the characteristics of high efficiency and high precision, and the complex machining can be completed as soon as the workpiece is clamped once. It can be suitable for the processing of present moulds such as auto parts, aircraft structural parts, etc. There is a big difference between five axis machining center and pentahedral machining center. Many people don’t know this. They mistakenly regard the pentahedron machining center as a five axis linkage machining center. Five axis machining center has x, y, Z, a, C five axis, XYZ and AC axis to create five axis machining, specializing in space surface processing, special-shaped processing, hollow processing, drilling, oblique hole, oblique cutting, etc. The “pentahedron machining center” is the same as the three-axis machining center, but it may as well do five faces at the same time, but it can not do special-shaped processing, such as drilling, cutting bevel, etc.

For the rest, the practical boundary of the five axis CNC machining center is quite ordinary. It is understood that the current five axis CNC machining center system is the only way to process impellers, blades, marine propellers, heavy-duty generator rotors, automobile wheels, large diesel engine crankshafts, etc.

2、 Advantages of five axis machining center

1. Reduce processing time and improve processing accuracy.

The biggest feature of the five axis machining center is that it is advisable to process all five surfaces by one-time clamping. That is the so-called processing angle avoidance. If it’s a linked bed, axis C can rotate endlessly, and axis a can rotate by 130 degrees. These characteristics of the equipment make it possible to process without interference.

The advantage of this method is that one-time clamping can not only finish the processing, but also prevent the repeated positioning deviation caused by repeated clamping. At the same time, it also saves a lot of time and improves the working efficiency. It can reduce the time from product to delivery and reduce the inventory.

2. Reduce equipment investment cost, workshop area and workshop number.

The five axis linkage machining center controls the compound machining machine, usually with turning performance, which can be included from lathe to milling machine to vertical mill. Everyone knows that the value of vertical mill equipment is quite high at present. After cost, processing beat and other accounting, we can find that the value of five axis is high. Before that, the majority of people’s production and processing may be based on engineering segmentation. The problem with such a production method is that there is a lot of waiting time that cannot be eliminated. However, the engineering intensive production represented by the five axis compound processing equipment only needs the early waiting time for debugging, and with the popularization of all kinds of complete machine simulation software in China at present, even if only the blank data is imported, the programming can be completed and the early planning can be greatly reduced. So at present, overseas auto parts and high-end manufacturing are basically based on five shafts.

3. No need for unique fixture, can complete automation.

Another prominent feature of the five axis is that the dependence on the fixture will be reduced. The rule workpiece can be clamped directly with three claws and four claws chuck, while the rule workpiece can be clamped with one side and two pins. At the same time, the five axis machining center can complete the automation of the workshop and reduce the number of people. For example, machining robot’s key point and base. In the past, horizontal plus and vertical plus combined processing were used. Now, only zero point tray and five axis linkage processing center are used to complete 24-hour operation processing.

Advantages of non-standard precision parts processing

The advantages of non-standard precision parts machining center is developed from CNC milling machine. The biggest difference between CNC milling machine and CNC milling machine is that the machining center has the strength of automatic interchangeability of machining tools. Through the installation of different purpose tools on the tool magazine, the machining tools on the spindle can be changed through the automatic tool change device in a clamping process to complete a variety of machining performance. The non-standard and sophisticated parts processing equipment is suitable for a large number of high-precision and complex processing, and it is more and more competent for arc, taper and other processing. The advantages of non-standard parts processing small non-standard parts processing from one to three digits, is through simple mold, soft mold, perhaps directly out of the processing.

The processing of non-standard precision parts is usually a normal machining process such as turning, milling, planing, grinding, pliers, etc., and the fitter’s blanking, drawing lines, drilling, tapping, etc. Representative industries include aviation, aerospace industry, ship industry, construction machinery industry, machine tool industry, etc. The typical representative of mass production is the automobile industry, while the new model and the first-class trial production of the automobile industry and the mold industry focusing on mass production service are still a single small batch production. The advantages of non-standard parts processing small batch production may well save time and raw material cost, and speed up the product market cycle. Small batch production is closely related to hand plate mold. Hand plate mold is the condition of small non-standard parts processing, while small non-standard parts processing is based on hand plate mold.

How to improve the efficiency of CNC machining

With the recent development of China’s machining and manufacturing level, CNC machining technology is still widely used. Many enterprises still possess the international advanced CNC machining equipment

However, the phenomenon of “heavy equipment light technology” exists widely

How to improve the efficiency and quality of machining

The falling technology level greatly affects the development of advanced equipment manufacturing strength

High advanced equipment can not fully develop its production strength, which means cost.

The above situation directly affects the market competitiveness of enterprises

Pay attention to processing technology and improve production efficiency

“Technology” is the core of machining;

Therefore, the emphasis on “technology” is a good way to improve the production efficiency;

Indeed, we will raise the technological level, complete efficient manufacturing, high-quality manufacturing and economic manufacturing, and achieve the sustainable competitiveness of the enterprise with high technology.

Conclusion: clamping method is the core factor of decision-making efficiency and quality control. So usually the first question many customers ask is the proportion of teachers and fathers in your workshop,

What are the advantages of non-standard precision parts machining

What are the advantages of non-standard precision parts processing? The advantages of non-standard precision parts machining center is developed from CNC milling machine. The big difference between CNC milling machine and CNC milling machine is that the machining center has the strength of automatic interchangeability of machining tools. Through the installation of different purpose tools on the tool magazine, the machining tools on the spindle can be changed through the automatic tool change device in a clamping process to complete a variety of machining performance. The non-standard precision parts processing equipment is suitable for large quantity, high precision and complex processing, and it is more and more competent for the processing of arc and taper. The advantages of non-standard parts processing small non-standard parts processing from one to three digits, is through simple mold, soft mold, perhaps directly out of the processing.

Precision parts processing

The processing of non-standard parts is usually a normal machining process, such as turning, milling, planing, grinding, pliers, etc. the fitter’s cutting, drawing, punching, tapping, etc. Representative industries include aviation, aerospace industry, ship industry, construction machinery industry, machine tool industry, etc. The typical representative of mass production is the automobile industry, while the new model and the first-class trial production of the automobile industry and the mold industry focusing on mass production service are still a single small batch production. The advantages of non-standard parts processing small batch production may well save time and raw material cost, and speed up the product market cycle. Small batch production is closely related to hand plate mold. Hand plate mold is the condition of small non-standard parts processing, while small non-standard parts processing is based on hand plate mold.

What are the reasons for the rough surface of precision parts

The key reason of processing technology, from the perspective of our careful hardware technology, there were many reasons that would have a positive impact on the surface roughness of its parts. The key point is that the tool still has the material of the workpiece, and it is formed due to the condition of numerical control. As for the geometric reason, if it is mainly affected by the tool form, the deflection angle of the deflection angle pair and so on will have a greater impact on the surface roughness.

When we reprocess plastic raw materials, we will also form strip cutting to form accumulated cutting tumor, and the hardness is still very high. In the process of workpiece cutting, the blade fillet and extrusion can deform the metal raw materials, which will cause the surface to become rough and critical, and the surface function of accumulated cutting tumor will be completely irregular, so it is very simple to make the workpiece surface appear different knife marks in depth, width and width. For example, the rotation speed does not match the cutting speed, the raw material is too hard and the cutter is too much, the workpiece is not compressed, the workpiece elasticity is too large, the rubber finished products such as the cutter body is too long, the cutter bar vibrates during processing, the machine tool itself such as: the movement gap of lead screw line rail is too large, etc. All of these will inevitably increase the roughness of the part surface.

How to choose the cutter for CNC machining

1. Surface trenching

It is mainly about the selection of boundary line and face.

The machining area of the tool path is based on the principle of taking the selected surface within the selected boundary as the end surface and all the places that the tool can go from the high point of the reference to the low point of the reference. If the selected surface is well controlled, it is the whole surface, and the boundary can only be the area to be processed. If there is no surface, the extension is less than the interval of half the cutter diameter, because there is sufficient margin for other surfaces, it will be automatically protected; if the selected surface is well controlled, the extension is low line, because there is less than one R gong at the low point of the control.

Selection of cutter: if the cutter can’t enter the helix or oblique line, or the machining area can’t enter the cutter, seal it up, and leave it to be cut twice.

Before the smooth knife, it is necessary to make all the areas that have not been cut thick, especially the small angle, including the two-dimensional angle, the three-dimensional angle and the sealed area, otherwise the knife will be broken. Secondary cutting: it is usually used to select the boundary line with three-dimensional cutting, flat bottomed cutter, and it is used for those who can use plane cutting and appearance cutter path. Under the condition of no damage to other surfaces, the center of the tool to the selected boundary is usually not refined, depending on the situation with a quick two-way angle, spiral feed, angle of 1.5 degrees, height of 1. When the form of excavation is strip, oblique feed is used when spiral cutting is not possible, usually open the filter, especially when the surface is rough, the feed plane cannot be low, so as to avoid hitting the knife, the safe height cannot be low.

Withdraw knife: usually do not use relative withdraw knife, use absolute withdraw knife, when there is no island, use relative withdraw knife.

2. Plane slotting: milling all kinds of plane, concave and flat groove. When milling part of the open plane, it is necessary to determine the boundary. In principle, it can feed (more than one diameter), the opening part is more than half of the diameter, and the periphery is closed tightly.

3. Appearance: when the selected plane is suitable for appearance layering, use the appearance layering to lift the knife (plane appearance). When the lifting point and the lower cutting point are one point, the z plane does not need to lift the knife normally, although the relative height is not used; the correction target is usually right (along the knife).

4. Tool path configuration of mechanical correction: the correction number is 21, and the computer correction is changed to mechanical correction. The feed is vertical feed, and the area where the knife cannot pass is increased by R without margin.

5. Contour appearance: it is suitable for tight closed surface, open surface. If there are four circles, the item surface shall be sealed. If there are four circles or not, the boundary and height shall be selected (the arc feed must be rough). It is used for rough condition: the machining interval in any plane is less than one cutter diameter, and if there is more than one cutter diameter, the larger cutter or twice contour appearance shall be used.

6、 Curved streamline: with good contrast of average and neatness, suitable lightsaber can replace contour appearance for many times.

7. Radial knife path: suitable for the condition that there is a large hole in the middle (less use). Attention: when the knife is not sharp, the knife is too long. When the workpiece is too deep, it should not go up or down around; the surfaces on both sides of the sharp corner of the workpiece should be divided into two knife paths, which should not go out. When the knife is smooth, the edge should be lengthened (use arc to advance or retreat the knife).

Key points of automatic machine debugging

First of all, according to the requirements of the footnotes, add oil to each smooth point, fill the hydraulic oil tank with qualified hydraulic oil, connect the air source and power on. After the farewell power supply of each component or the sequential power on test of each component, the whole power supply shall be carried out to see whether each component has alarm, whether each manual component is normal, and whether each safety device works, that is to say, all links of the machining center of elaborate parts shall be able to monopolize and act independently.

The second is debugging. Plan all kinds of testing equipment, such as careful level, standard square ruler, parallel square tube, etc., fine adjust the level of the machine tool, so that the geometric accuracy of the machine tool for processing the detailed parts reaches the boundary of the allowable deviation, select multi-point pad to maintain, adjust the bed to the level in free form, and the stability after the body adjustment.

The three steps are to adjust the position of the manipulator with respect to the main shaft by the method of manual exclusive control. When installing the large-scale tool handle, the tool magazine shaft shall be exchanged automatically for many times, so as to ensure accuracy and no impact.

The four steps are to check whether the setting parameters of the CNC system and PLC device of the programmable controller conform to the articles of association data in the random materials, and then test the performance of each key point, safety countermeasures, implementation of common instructions, etc.

The fifth step is to check the working condition of accessories, such as lighting, cooling, smoothness, protective cover, various protective plates, etc. After the completion of installation and commissioning, carry out various tests, generally including: operation test (including performance test, empty operation test and continuous empty operation test), load test, vibration resistance test, feed test against small set unit, return to reference point test, machine accuracy check, incremental cutting test of tools, etc