With the increase of labor costs and the gradual improvement of product requirements in the sheet metal processing industry, the profit stream of sheet metal processing is getting narrower and narrower. The efficiency can not be raised, and even the production will be at a loss.
Sheet metal manufacturing enterprises are trying to use robots or automatic equipment to replace labor, so as to reduce processing costs and improve production efficiency.
Some enterprises try successfully but pay a considerable cost. After most enterprises adopt robots and automation equipment, they not only fail to achieve the expected effect but also make it trapped equipment.
The customer opened the door to receive orders during the visit. The vast majority of idle robots or automation equipment is not that the equipment can not be used or difficult to use, but that sheet metal enterprises do not deeply analyze their product process and output and do not understand the performance and limitations of automation equipment before purchasing robots or automation equipment.
For the sake of performance, the salesperson of automation equipment exaggerates the equipment performance, and the purchasing enterprise mistakenly thinks that the automation equipment purchased by themselves is omnipotent.
When the automation equipment is put into production, 30% of the products can realize automatic production, and 70% of the products also rely on manual production, so the utilization rate of automation equipment is very low.
The most perfect automation equipment has its limitations, so before adopting automation equipment, we must carefully analyze the process and batch of enterprise products and analyze the performance and limitations of automation equipment.
Let’s share the investment and selection of sheet metal process automation equipment.
Full automatic production can be realized by adding automatic loading and unloading device.
Laser loading and unloading selection
The cantilever suction cup belongs to a semi-automatic feeding device, which is economical and suitable for feeding thin plates with a thickness of less than 5m and a weight of less than 20kg.
However, if the cantilever semi-automatic method is adopted for feeding thick plates, it will be very difficult to manually push the suction cup, so it is not recommended to use it.
The gantry automatic feeding device is suitable for thick plate and large plate feeding, with good safety and high efficiency.
It is not recommended to put the automatic device into automatic laser blanking. Laser processing is mainly small batch and multi-variety.
Automatic blanking reduces the processing efficiency. If the production batch is very large, it is recommended to use laser coil cutting production line to save materials. High processing efficiency.
Selection of NC blanking and loading
The advantages of unilateral automatic loading and unloading device are:
The loading and unloading are on the same side, and a cycle of loading and unloading takes 35 ~ 40 seconds. The floor area is small. The material warehouse can be expanded and added without increasing the floor area;
The advantages of automatic loading and unloading devices on both sides are:
The loading and unloading efficiency is higher than that of one side. The loading and unloading cycle can be completed in 16-20 seconds, but the floor area is relatively large, which is suitable for sheet metal enterprises with the unrestricted site.
More than 3 CNC presses are suitable for adding automatic loading and unloading devices. In one case, one person can operate three CNC presses with automatic loading and unloading devices, and one shift can reduce 3-4 operators.
Moreover, it reduces the labor intensity of operators and liberates the mechanical repeated loading and unloading work.
Operators have more time to consider the preparation before processing, such as die preparation, material preparation and optimization of processing procedures, which can greatly improve the processing efficiency.
The NC punching automatic loading and unloading device is also a very mature scheme.
Press brake forming
98% of sheet metal forming plants use press brake machines.
This kind of equipment has a small investment and can be processed in general. The only drawback is the need for manual operation.
When processing workpieces with length and width greater than 50mm, it is difficult to operate by one person, and more than two workers are required to cooperate in processing (Fig. 1).
The bending efficiency is low and industrial accidents are easy to occur when processing plates with a thickness of more than 2mm.
Bending work is hard and takes a long time to learn and accumulate experience. The salary of bending is higher than that of other types of work.
Robot bending and servo-assisted bending are two automation schemes to reduce labor cost.
(1) Robot bending.
After debugging the equipment in this way, the fully automatic production without shutdown can be realized.
Long-term processing is more efficient than manual processing. One commissioning personnel can operate multiple press brake machines.
Its disadvantage is that the debugging time is too long, the requirements for operators are relatively high, it is not suitable for multi-variety and small-batch processing, and different products need to replace the suction cup frame.
Many enterprises have invested in robot bending. Due to the insufficient batch of fixed product orders, the operators are not familiar with debugging, resulting in idle equipment.
Fig. 1 Traditional bending
(2) The bending is assisted by the sheet followers (Fig. 2).
This method can be used for multi-variety and large and small batch production. The advantages of the large workpiece and thick plate bending are obvious, reducing bending auxiliary personnel (Fig. 3), reducing labor intensity and strong flexibility.
One sheet follower can be used with multiple press brakes, and the investment cost is relatively low.
The disadvantage is that manual loading and unloading operation is required, and automatic production cannot be fully realized.
Fig. 2 Sheet follower
Fig. 3 Bending with sheet follower
The panel bender has high processing efficiency, can realize full-automatic production, and is suitable for complex chassis processing.
It is not allowed to bend thick plates and products with hem higher than 300mm, which has high input cost and maintenance cost and can not be bought by factories of general scale.
The profit of sheet metal processing is too low, and it is difficult to recover the cost after investment.
The main work of sheet metal fitters is drilling, tapping and countersunk.
Some sheet metal products need aluminum profile processing, avoidance steps, blind holes and fish eye pits. Traditional processing equipment includes bench drill, table tapping machine and milling machine.
Manual operation of assembly line operation is prone to quality accidents, such as hole leakage, tooth leakage and so on.
More complex parts may have a variety of tapping, counterbore and reaming processes of different specifications.
Traditional equipment processing is more troublesome. It requires many people to cooperate, and the efficiency is also low. Many sheet metal enterprises use drilling, tapping and milling centers (Fig. 4).
Fig. 4 Drilling and tapping center
Drilling, tapping and milling center is numerical control equipment integrating the functions of drilling machine, tapping machine and milling machine.
It has offline programming and automatic tool change of multi-station tool library.
Clamp multiple parts at one time, and automatically process all holes, tapping, gap milling and other processes of the parts according to the program.
It can clamp and disassemble the parts without stopping. It has high efficiency (40-60 holes can be processed per minute) and can process profile radiator products.
The defect is that it needs to program and make tooling fixtures, which is not suitable for proofing or processing of sample products.
Welding and grinding process
Manipulator welding is a very mature automation scheme, which will not be introduced here. Grinding is the process bottleneck of all sheet metal enterprises.
The grinding work is dirty, tired and the environment is bad, and the grinding process is an essential process for sheet metal processing.
Grinding workers are very difficult to recruit. The grinding work is basically supported by the post-60s and post-70s.
Young people are unwilling to engage in it, so the grinding cost is also very high. Some sheet metal enterprises learned from the experience of hardware polishing automation and tried robot polishing, most of which ended in failure.
Now the five-axis CNC grinding workstation (Figure 5) is relatively mature and recommended to you.
The five-axis CNC grinding workstation is used to grind the weld scar on the surface of the sheet metal workpiece.
It is suitable for grinding and polishing the surface of the box body, cabinet body, door panel and internal structural parts.
It is mainly used in communication equipment, power equipment, medical equipment, environmental protection equipment, electronic equipment rack, safe body and other related industries, replacing traditional manual grinding and improving factory processing efficiency, shorten sheet metal processing time.
The workstation adopts manual material handling, the workpiece is fixed on the workbench, and the X/Y/Z/B/C servo is positioned and rotated, which greatly improves the accuracy and response speed of the equipment;
The platform adopts large-diameter screw guide rail, which not only ensures the accuracy but also improves the stability of the workbench;
The 5-axis CNC system, combined with bus service and intelligent manual teaching technology, solves the problem of professional programming in sheet metal enterprises, reduces the skill requirements for operators. It is simple and fast and has strong timeliness in transforming products.
The defect is that it is not suitable for grinding small-batch products, and tooling fixtures need to be made (the tooling fixtures for grinding are relatively simple and the cost is not high). The interior and small corners of some products cannot be polished.
Fig. 5 Five-axis grinding workstation
The selection of sheet metal automation equipment does not have to be expensive. Imported automation equipment may not be easy to use, but the cheapest one must not be easy to use.
Sheet metal enterprises should choose automation equipment according to their own product characteristics, which is valuable.