2020 – Page 88 – CNC Machining & Turning, Milling, Metal parts

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

Operation steps of fixture accessories

(1) Install the two pieces of No. 4 engine liners on the No. 1 strut in accordance with the “strut welding combination” drawing, and place them on the clamp details, position the No. 1 strut by the stop pin and baffle plate, and clamp the No. 1 strut by the screw clamp; at the same time, position the two pieces of No. 4 engine liners by the bolt, and clamp them by the quick withdrawal screw clamp device;

(2) After tack welding, loosen the quick withdrawal screw clamping device, pull out the bolt and take it down for welding;

(3) Place the weldment on the clamp details, position the weldment by the stop pin and baffle plate, and clamp the weldment by the screw clamp; then place the components of NUT M6 and horn support on the weldment, and position the weldment by the screw clamp organization by the taper pin on the screw clamp organization and the open groove on the press plate of the screw clamp organization;

(4) Weld the assembly of NUT M6 and horn support and strut on three sides, and then loosen all screw clamps. The pressing plate of screw clamping organization of the assembly of clamping nut M6 and horn support is springed up by spring, and the locating cone pin on it gets rid of the weldment, then push out the pressing plate to get rid of the screw clamping organization stud at one end, turn the pressing plate to one side of the weldment, and then take out the weldment 。

What are the characteristics of inspection tool accessories

1) What are the characteristics and advantages of flexible inspection tool compared with traditional inspection tool?

The flexible inspection tool has some unique advantages that the traditional inspection tool does not have. The key points include: a flexible inspection tool can measure the difference products (one to many or adjustable, thrifty storage space, components can be repeatedly used), automatic measurement, automatic data recording, high measurement accuracy, not afraid of deformation (low cost), short development cycle, etc.

2) Can flexible inspection tool replace traditional inspection tool?

The flexible inspection tool is an important supplement to the traditional inspection tool. For example, when the space is small and it is difficult to install the probe, the traditional inspection tool can only be used. The flexible inspection tool can not completely replace the traditional inspection tool.

3) How to ensure the accuracy of flexible inspection tool?

The accuracy of the flexible inspection tool is guaranteed by the accuracy of the probe. As the probe may be reset to zero, even if the tooling accuracy is low or deformed, as long as the probe is reset to zero from the beginning, the system may automatically complete compensation, which will not affect the use.

4) What are the disadvantages of flexible inspection tools?

The measuring deviation of the flexible measuring tool is measured by the probe method, so the measuring points are separated; while the traditional measuring tool is based on the reference profile, and the measuring points are continuous. The flexible measuring tool is an automatic measuring device, which needs a stable power supply; the traditional measuring tool is usually a pure mechanical measuring device, which usually does not need a power supply

What are the characteristics of inspection tool accessories

1) What are the characteristics and advantages of flexible inspection tool compared with traditional inspection tool?

2) Can flexible inspection tool replace traditional inspection tool?

3) How to ensure the accuracy of flexible inspection tool?

4) What are the disadvantages of flexible inspection tools?

The future development trend of gantry milling

1. Performance development trend

Efficiency, speed and precision are the main performance indicators of machining. The high-speed CPU chip, multi CPU control system and AC digital servo system are selected for large-scale CNC Longmen milling. At the same time, countermeasures such as improving the dynamic and static characteristics of the machine tool are adopted to greatly improve the speed efficiency and precision of large-scale CNC Longmen milling. At present, the MTBF value of the numerical control device used in the large-scale CNC gantry milling processing equipment overseas can reach more than 6000h, and the MTBF value of the servo system can reach more than 30000h, with high reliability. With the development of science and technology in the future, the CPU chip will reach a higher speed, the servo system will be improved, and the performance of large-scale CNC gantry milling will be improved.

2. Performance development trend

CNC system is an important part of large-scale CNC gantry milling. Operators operate through the user interface near the CNC system, so as to operate large-scale CNC gantry milling to process workpiece. Due to the different requirements of different users for the interface, the workload of opening up the user interface is huge. The user interface has become one of the difficult parts in the development of computer software. The appearance of the graphical user interface greatly simplifies the use of non special users. People may as well operate through the window and menu, which is convenient for blueprint programming and rapid programming, 3D color three-dimensional dynamic graphics Display, graphic simulation, graphic dynamic tracking and simulation, view of different targets and one-sided display scale performance. With the upgrading of CNC system and the upgrading of user interface, the future performance of large-scale CNC gantry milling will be further developed.

3. Structure development trend

At present, the high integrated CPU / RISC chip, FPGA / EPLD / CPLD and ASIC chip are used in large-scale CNC gantry milling, which can improve the integration degree of CNC system and the operation speed of software and hardware. FPD flat panel display technology can improve the performance of the display device. The flat panel display device has the advantages of high technology content, light weight, small size, low power consumption, easy to carry and so on. It can complete large-scale display, becoming a new display technology that resists CRT. It is the mainstream of display technology in the 21st century. Advanced packaging and interconnection technology are used to integrate semiconductor and surface installation technology, By increasing the density of integrated circuit and reducing the number and length of interconnection, the product value, performance, component size and reliability of the system can be reduced. With the further development of intelligent technology, the volume of chips and integrated circuits will be smaller, and the structure of large CNC gantry milling processing equipment will be greatly improved.

How to choose the cutting tool for machining hardware parts

CNC milling machine is divided into two categories: without tool library and with tool library. The CNC milling machine with tool library is also called machining center. Be able to process sophisticated hardware parts with unique and complex appearance or difficult to control size, such as mold parts, shell parts, etc. The cutting tool used in the machining center of the sophisticated hardware parts is composed of the general cutting tool and the tool handle matched with the taper hole at the front end of the spindle of the machining center. In the process of machining, there are many factors to be considered, such as the function of the machine tool, the rigidity of the fixture, the function of the workpiece raw material, the cutting amount and other related factors.

The general principle of tool selection in machining center is: good rigidity, easy installation and adjustment, high durability and precision. In addition, in order to increase the rigidity of the tool and ensure safety, the extension length of the tool should be as short as possible. On the machine tool of the sophisticated hardware parts processing center, all kinds of tool farewell are installed in the tool magazine and processed according to the regulations of the program.

Variety of cutting tools in machining center: there are many kinds of cutting tools in the machining center of well-designed hardware parts, which are widely used and compared with various kinds of surface and hole machining tools. The milling cutters of various types are mainly selected for the machining of plane and curved surface, while the hole machining tools can select drills, reamers, reamers, boring cutters, etc. according to the form, location and accuracy requirements of the holes to be machined. The carbide spiral end milling cutter is mainly used for processing cast iron, steel, non-ferrous metal and other materials. The blade is usually welded. The indexable spiral end milling cutter is mainly used for rough milling of large workpiece steps, elevations and large grooves.