เวลาอ่านโดยประมาณ: 11 นาที

How to Choose A Used Bending Machine

1. ใช้แล้ว Bending Machine Purchase Route

You can consider buying used bending machines, and some Japanese used bending machines and shears from European and American countries. Select some of the best domestic manufacturers of bending machines, you can go to the official website of large companies to view information, or contact the procurement department of large enterprises, ask their companies used equipment disposal matters. Several used machine tool markets deal in used bending machine shears, such as Vigert used equipment network.

2. Precautions When Buying Used Bending Machines

The first concern is the hydraulic system of the used bending machine shears, if trading with a used bending machine broker, it is best to let it show the bending machine factory date, factory information. A good used bending machine shear, its hydraulic system is more stable, no repair starvation traces, two often repair used machine tools, many parts may be new, indicating that the machine itself has problems, need to be careful to buy. Then focus on used bending machine after the gear material, good used bending machine after the gear material, easier to operate, the workmanship is relatively fine, for used bending machine several into the new hunger problem, this last view factory information, no words, view part of the old parts of the factory time, the general machine tool color is difficult to determine its factory time. Finally, you can consider the used bending machine shearing machine control system, the general choice of stable CNC system, the best to understand the situation of their CNC system, try the stability of the CNC system.

3. Used Bending Machine Quality Measurement

For used bending machine quality measurement, there is not a perfect standard, I can only recommend some of their own experience, for ordinary used bending machine shearing machine, first look at its bending machine brand, see is genuine, or label, two prices vary greatly, it is best to let the manufacturer show its factory information, then look at the hydraulic system new and old, as well as the use of years, the overall performance of the machine, and finally Look to sell used bending machine manufacturer’s information, to judge the credibility of this enterprise, many customers are prone to negligence, it is necessary to ask whether the used bending machine is in stock and can be viewed.

4. Used Bending Machine Price Estimates

The first depreciation method, view the current market price of new machines for this second-hand bending machine tool, and then by this on the approach to judge. The second approach, the comparison method, finds a few more manufacturers to ask the price, you can understand the price of used bending machines. The third approach, check the market price of iron, has been some important parts of the price, according to 30% to convert the price, this is only some experience approach, specifically, some manufacturers may have replaced part of the parts, which requires their judgment, specific analysis of specific problems.

5. Used Bending Machine Appreciation Approach

Used bending machine CNC conversion, used shearing machine transformation upgrade: If customers buy a used bending machine or shearing machine, the accuracy is not high, can not meet the needs of product production, you can consider used bending machine CNC conversion, used shearing machine transformation upgrade, generally used bending machine shearing machine conversion upgrade, you can replace the backstop, control system, which is equal to the important control part of the machine tool replacement, while used Bending machine shearing machine overall frame if excellent, fully comparable to imported, or top domestic machine tools, cost-effective, customers can consider.

Basic Information About Bending Machine You Need to Know

Now with the development of the market economy, the machinery manufacturing industry, hardware industry soared. Bring a large number of people from different industries to join the ranks. Therefore, many friends for the purchase of machine tools do not know how to start. Special to the new friends in the industry to introduce the basic procurement knowledge of bending machines.

1. Bending Machine Domestic Model Introduction

WC67Y series, WC67K series, WD67Y series, WE67K series.

To illustrate.

WC67Y 100/4000

W – bending machine code

A means table upward movement, this machine is mostly seen in the old imported machine, its synchronization is poor, now on the market to rare.

B means hydraulic synchronization of parallel cylinders, mostly single-cylinder machines. The hinge connection is used. Nowadays less used for small tonnage bending machines.                                                        

C means synchronous bending machines with twisted axes. Now widely used synchronizing mechanism. It has good synchronization and can be used for small offset loads. It is now used by all manufacturers. There are also two types of twist-axis synchronization, distinguished by how the slider travel is positioned. One is the built-in type of cylinder and the other is the independent turbine worm positioning, which has a higher configuration and is a new design and easy to maintain.                                       

D means machine-hydraulic synchronization, through the mechanical transmission control of the oil cylinder oil intake, to achieve the synchronization of the two cylinders. Mostly used for bending machines with a processing width of 6 meters or more.

E means Electro-hydraulic synchronization, the signal is transmitted to the computer through the scale. After analysis, the computer then transmits the signal to the electro-hydraulic servo-proportional valve, which controls the slider action, and then detects the signal on the slider to compensate, forming a closed loop with high positioning accuracy.

K means computer control. There are various control systems. Economic CNC, high precision CNC. The economical CNC is mostly used for twist axis synchronous bending machines to achieve automatic control of the backstop and slide stroke adjustment.

Y means hydraulic drive.

100 is the tonnage of the bending machine.

4000 is the table length.

2. The Following Factors Are Taken Into Account

The first important thing to consider is the part you want to produce. The point is to buy a machine that can do the job with the shortest table and the smallest tonnage. Consider carefully the grade of material and the maximum thickness and length to be machined. If most of the work is in mild steel of 16 gauge thickness and a maximum length of 10 feet, then the free bending force does not need to be greater than 50 tonnes. However, if you are doing a lot of undercuts die forming, you should probably consider a 150-tonne machine. Assuming the thickest material is 1/4″, a 10′ free bend would require 165 tons, and a bottom dies bend (calibrated bend) would require at least 600 tons. If the majority of the workpiece is 5ft or less, the tonnage is almost halved, thus significantly reducing the cost of purchase.

Deflection: You also have to consider the deflection that can occur on this machine. A 10ft machine will experience four times more deflection in the table and slides than a 5ft machine under the same load. This means that a shorter machine will require less shim adjustment to produce a satisfactory part. The reduction in shim adjustment also reduces set-up times. The grade of material is also a key factor. Compared to mild steel, stainless steel usually requires about 50% more load, while most grades of soft aluminum require about 50% less. You can always obtain a table of machine tonnages from the bending machine manufacturer, which shows an estimate of the tonnage required per foot of length for different thicknesses and materials.

Bending radius of the part: In free bending, the bending radius is 0.156 times the opening distance of the die. In free bending, the die opening distance should be 8 times the thickness of the metal. If the bending radius is almost as small as the thickness of the material, undercutting is necessary. However, the pressure required for undercutting is about four times greater than for free bending. If the bending radius is less than the material thickness, a die with a radius of the front corner less than the material thickness must be used, and recourse must be had to the embossed bending method. In this case, 10 times more pressure is required than for free bending. In the case of free bending, the cam and concave dies are machined at 85°or less. With this set of dies, attention is paid to the clearance between the cam and concave dies at the bottom of the stroke and to the overbending sufficient to compensate for the rebound and keep the material at around 90°. As a rule, the free bending die produces a rebound angle of ≤ 2°on the new bending machine and a bending radius equal to 0.156 times the opening distance of the concave die. For concave bending with a bottom die, the die angle is generally 86 to 90°. At the bottom end of the stroke, there should be a gap between the die and the die that is slightly greater than the thickness of the material. The forming angle is improved by the higher tonnage of undercut die bending (approximately 4 times that of free bending), which reduces the stresses that normally cause spring back within the bending radius. Impression bending is the same as bottom die bending, except that the front end of the die is machined to the required bending radius and the die gap at the bottom of the stroke is less than the material thickness. Springback is largely avoided by applying sufficient pressure (approximately 10 times that of free bending) to force the front end of the die into contact with the material. To choose the lowest tonnage specification, it is best to plan for a bending radius greater than the material thickness and to use the free bending method as much as possible. Larger bending radii often do not affect the quality of the finished part and its future use.

Accuracy: Bending accuracy is a factor that needs to be carefully considered, and it is this factor that determines whether you need to consider a CNC bending machine or a manual bending machine. If bending accuracy of ±1°is required and cannot be varied, you must look at a CNC machine. The repeatability of the CNC bending machine slide is ±0.0004″, and forming precise angles requires such accuracy and good tooling. Manual bending machines have a repeatability of ±0.002″ and will generally produce ±2 to 3°of deviation with the right tooling. In addition, CNC bending machines are ready for quick tooling, which is a no-brainer when you need to bend many small parts. 

Tooling: Even if you have a shelf full of tooling, don’t assume that it is suitable for a newly purchased machine. Each die must be checked for wear by measuring the length from the front of the die to the shoulder and the length between the shoulders of the concave die. For conventional dies, the deviation should be around ±0.001 inch per foot and the total length should be no greater than ±0.005 inch. For fine grinding dies, the accuracy should be ±0.0004 inch per foot and no more than ±0.002 inch overall. It is best to use the fine grinding tooling for CNC bending machines and the conventional tooling for manual bending machines. Indeed, we often make the mistake of buying a new bending machine without the right tooling to match it.

Bending edge length: A factor that is often overlooked is the length of the bending edge of the material before the bending machine. Assuming a 90°bend along with a 5 x 10-foot sheet of 10-gauge mild steel, the bender must apply roughly 7.5 additional tons of pressure to lift the sheet, and the operator must be prepared for a 280-pound straight edge drop. Several strong workers and even a crane may be required to manufacture the part. Bending machine operators often have to bend long-sided parts without realizing how much work they are doing. There is now a pallet device suitable for workshops doing this kind of work, which can be adapted to the needs of new and old machines. With this device. Only one person is needed to form long-edge parts.