In the sheet metal processing industry, with the increase of labor cost and the gradual improvement of product requirements, the profit is getting thinner and thinner, and the efficiency cannot be raised or even the production will be at a loss.
Therefore, sheet metal manufacturing enterprises are trying to adopt robots or automation equipment instead of labor in order to reduce processing costs and improve production efficiency.
Some enterprises have succeeded in the transformation, but most of them have not only failed to achieve the expected results after investing in robots and automation equipment, but also the equipment has been idle and only opened up to support the facade to receive orders when customers visit them.
Most of the idle robots or automation equipment are not because the equipment does not work or does not work well, but because the sheet metal enterprises do not deeply analyze their own product process and output before purchasing the robots or automation equipment, and do not understand the performance and limitations of the automation equipment.
Moreover, some salesmen of automation equipment exaggerate the performance of the equipment for the sake of performance, and the purchasing enterprises mistakenly think that the automation equipment they purchase is a panacea.
After the equipment is put into operation, 30% of the products can achieve automated production, 70% of the products have to rely on manual production, the utilization rate is very low.
Any perfect automation equipment has its limitations, so before putting in automation equipment, you must carefully analyze the process and output of your company’s products and analyze the performance and limitations of automation equipment.
In this article, we will share with you how to configure sheet metal automation equipment and make the correct selection.
At present, the basic blanking equipment is laser cutting machine and CNC punching machine.
They are numerical control equipment, the degree of intelligence is relatively high, the addition of automatic loading and blanking devices can achieve fully automated production.
Laser loading and blanking
Laser automatic feeding is not recommended to put into automatic devices, laser processing is mainly small-batch multi-species, automatic blanking in turn reduces the processing efficiency.
For very large production quantities, we recommend using a laser coil cutting line.
The coil cutting line saves material and has high processing efficiency.
The cantilever suction cup (Figure 1) is a semi-automatic loading device, which is economical and suitable for loading thin plates with thickness within 5mm and weight within 200kg.
If the thick plate is loaded by cantilever semi-automatic method, it will be very hard to push the suction cup manually, so it is not recommended to use it.
The single-beam truss fully automatic loading device (Figure 2) is suitable for loading thick and large plates with better safety and higher efficiency.
Figure 1 Cantilever laser loading and blanking machine
Figure 2 Single beam truss laser cutting loading and blanking machine
CNC punch press blanking
The advantages of single-sided automatic loading and blanking device (Figure 3) are:
- Loading and unloading on the same side, one cycle of loading and unloading takes 35 to 40 seconds, small footprint and can be extended to increase the magazine on the basis of no increase in footprint.
The advantages of two-side automatic loading and blanking device are
- The loading and unloading efficiency is higher than that of one side, and one cycle of loading and blanking can be completed in 16 to 20 seconds, but it covers a relatively large area and is suitable for sheet metal enterprises whose sites are not restricted.
Figure 3 Single-sided automatic loading and blanking device
More than 3 CNC punching machines are suitable for adding automatic loading and blanking devices.
In general, one person can operate 3 CNC punching machines with automatic loading and blanking devices, which can reduce 3 to 4 operators in one shift, and effectively reduce the labor intensity of operators and free the mechanical repetitive loading and unloading work, so that operators have more time to consider the preparation work before processing, such as preparing the mold, preparing the material and optimizing the processing procedure, which can greatly improve the processing efficiency.
CNC punching automatic loading and blanking device is also a very mature solution.
98% of sheet metal forming factories use press brake machines, which are small investment and can be used for general forming.
The only drawback is that manual operation is required. It is difficult for one person to operate a workpiece with a length and width greater than 500mm, so more than two workers are required to work with it, and the bending efficiency is low when processing a sheet with a thickness of more than 2mm and is prone to industrial accidents.
Bending work is more difficult and requires a long time to learn to accumulate experience, so the salary of press brake operators is higher than other types of work.
Robot bending, follow-assist bending and bending center are the three automation solutions to reduce labor costs.
Figure 4 Robotic bending
After commissioning the equipment in this way, it can realize continuous non-stop fully automatic production, long-term processing is more efficient than manual processing, and one commissioning staff can operate multiple bending machine processing.
Its disadvantage is that the debugging time is too long, the requirements for operators are relatively high, it is not suitable for multi-species small batch processing, and different products need to replace the suction cup frame.
Many companies have invested in robotic bending (Figure 4), which has caused the equipment to be idle due to the lack of fixed product order batches and the operator’s lack of familiarity with commissioning.
This method can be used for multi-species, large and small batch production.
The advantages of bending large workpieces and thick plates are obvious, reducing bending support personnel, reducing labor intensity and flexibility.
A sheet follower can be used with more than one press braking machine, the investment cost is relatively low.
The disadvantage is that it requires manual operation with loading and unloading, and cannot fully realize automate production.
Bending center has high processing efficiency and can realize fully automatic production, which is suitable for complex chassis processing.
It cannot bend thick plates and products with bending edges higher than 300mm.
With high input cost and high maintenance cost, general scale factories can’t afford it, and the profit of sheet metal processing is so low that it is difficult to get back the cost after investment.
The main work of sheet metal workers is drilling, tapping and countersinking holes, and some sheet metal products need to use aluminum profiles to process avoiding steps, blind holes and fisheye pits.
Traditional processing equipment includes table drill, table tapping machine, and milling machine.
Manual operation in assembly line is prone to quality accidents, such as missing holes, missing tapping and other phenomena.
For more complex parts, there may be a variety of different specifications of tapping, countersinking and reaming process, the traditional equipment processing is more troublesome, and requires the cooperation of more than one person, and the efficiency is also low, many sheet metal enterprises use drilling, tapping and milling center processing.
Drilling, tapping and milling center is a CNC machine integrating the functions of drilling machine, tapping machine and milling machine, with off-line programming and automatic tool change with multi-station tool magazine, clamping multiple parts at one time, and automatically processing all holes, tapping and milling notches of the parts according to the program.
It can realize non-stop clamping and dismantling parts, with relatively high efficiency, and can process 40 to 60 holes per minute, and can process profile radiator products.
The disadvantage is that it requires programming and making fixtures, which is not suitable for the processing of prototype or trial products.
Welding and grinding process
Robotic welding is a very mature automation solution and will not be introduced here.
Grinding is the bottleneck of all sheet metal enterprises.
The grinding work is dirty, tiring and in a bad environment, but the grinding process is an essential process for sheet metal processing, and it is very difficult to recruit grinding workers.
Some sheet metal enterprises have tried robot polishing with the experience of hardware polishing automation, but most of them ended up in failure, now the five-axis CNC polishing workstation is more mature and recommended to everyone.
Five-axis CNC grinding workstation is used to polish the weld scars on the surface of sheet metal workpieces, which is suitable for grinding and polishing the surface of boxes, cabinets, doors and internal structural parts, mainly used in communication equipment, electric power equipment, medical equipment, environmental protection equipment, electronic equipment racks, insurance cabinet bodies, etc.
It can replace the traditional manual polishing, which can effectively improve the factory processing efficiency and shorten the sheet metal processing time.
The workstation adopts manual material handling, the workpiece is fixed on the table, x/y/z/B/C servo positioning and rotation greatly improves the accuracy and response speed of the equipment.
The platform adopts large-diameter screw guide, which improves the stability of the table while ensuring the accuracy.
The 5-axis CNC system with bus servo and intelligent manual teaching technology solves the problem of specialized programming for sheet metal enterprises, reduces the skill requirements for operators, is simple and fast, and transforms the products with high timeliness.
The disadvantage is that it is not suitable for grinding small batch products, need to make tooling jigs (grinding tooling jigs are relatively simple and cost effective), and some products cannot be polished internally with small corners.
Automation of machine tool equipment and production mode is a major development trend in the sheet metal industry, and more and more sheet metal enterprises are starting to upgrade their automation, but automation transformation is not simply buying a bunch of equipment, but organically combining their own products with the equipment.
The selection of sheet metal automation equipment does not necessarily have to be expensive, imported automation equipment is not necessarily good, but the cheapest one must be bad.
Sheet metal enterprises should choose automation equipment according to their own product characteristics, so that they can have value.