Punching Machine

3 Amazing Things to Know About Punch Feeder

Featured picture of punch feeder

Estimated reading time: 11 minutes

The feeder is a piece of indispensable auxiliary equipment for the automatic operation of the press. Due to the wide variety of presses, the wide range of applicable materials, and the different processing techniques, many types of feeders have been born. Regarding these feeders, I believe you also have many questions, such as what kind of them, what are their functions, how to choose them, and so on. This article will be very helpful to you!

Classification And Characteristics

There are many types of punch feeders, and there are three commonly used types: air feeders, roller feeders, and NC servo feeders.

Air Feeder

Also known as pneumatic feeder, air feeder. Its principle is similar to that of a medical syringe. It is powered by an external compressed air source. The floating rod is pressed down by a rod installed on the punch slider, and a five-hole valve is operated to control the direction of compressed air to achieve the intermittent feeding goal.

Advantages of air feeder: The price is economical and affordable, and the automatic production of punch presses can be realized with a small investment.

But the air feeder also has obvious disadvantages:

  1. The feeding speed is slow. Due to the pressure and flow limitation of the external air source, the air feeder has a long action cycle and cannot meet the requirements of high-speed feeding. It is only suitable for use with low-speed punches.
  2. The feeding accuracy is poor and unstable. The working principle of pneumatic push type makes the air feeder clamp the material and push the material at the same time, and the material will be pushed when the material is not fully clamped. The material will slide unpredictably during the push, resulting in poor feeding accuracy; At the same time, the air feeder has many vulnerable parts such as O-rings, seals, etc. It is easy to cause failures such as air leakage due to inadequate maintenance, and cause unstable operation of the machine.
Figure 1-1 Punch air feeder
Figure 1-1 Punch air feeder

Mechanical Feeder

Also known as roller feeder, mechanical feeder. Its principle is similar to that of grinding tofu by stone grinding. The pull rod is driven by the output shaft of the punch, the pull rod pulls the rocker arm of the roller, and the rocker arm drives the transmission shaft. The unidirectional device converts the power of the reciprocating motion of the transmission shaft into the unidirectional feeding motion. At the same time, the roller feeder is equipped with a brake device to prevent the feeding roller from retreating.

The advantages of mechanical feeder: high-cost performance, no additional air source, power supply, high mechanical transmission stability, low failure rate.

But the mechanical feeder also has obvious disadvantages:

  1. After the feeding step needs to be stopped, the operator must adjust the eccentric disk installed on the output shaft of the punch, and it needs to be adjusted several times to calibrate.
  2. Installation is restricted. There are strict restrictions on the applicable material width, material thickness, and feeding step.
Figure 1-2 Punch mechanical feeder
Figure 1-2 Punch mechanical feeder

NC Servo Feeder

Also known as NC numerical control feeder, it realizes the feeding action by the feeding roller driven by the servo motor, and the control of the servo motor is completed by the touch screen and PLC. As the third-generation mainstream feeding equipment, the NC feeder can be divided into mechanical types in addition to the organic size and applicable material thickness (2.2mm, 3.2mm, 4.5mm, 6.0mm) according to its different relaxation methods. NC feeder and pneumatic NC feeder.

The mechanical NC feeder and the pneumatic NC feeder are the same in the feeding principle: they both use the touch screen to input the action instructions for the PLC (feeding length, feeding speed, feeding times, etc.), and then the PLC sends out a fixed number of high-speed pulses The operation of the servo drive is controlled, and then the rotation position and speed of the servo motor are controlled by the servo drive, and finally, the feeding roller is driven by the timing belt wheel to realize accurate feeding. The difference between the two types of feeders is mainly reflected in the realization of the relaxation action.

The pneumatic NC feeder is connected to the release cam group of the punch (traditional punches do not have a cam, and a cam piece needs to be installed), and the release cam of the punch provides a release signal to the solenoid valve of the feeder (traditional punch is equipped with a proximity switch). The release cylinder is controlled by a solenoid valve (or proximity switch) to push the feed roller to achieve a relaxation action, and its relaxation action is relatively slow; however, its advantage is that it can be used with various machine tools (including punches, shears, hydraulic presses, forming machines, Laser cutting machine) is used in a wide range of applications.

The mechanical NC feeder needs to install a loosening rod device on the punch cam. When the punch is punching, the rod is pressed to release the bearing to realize the synchronous relaxation of the upper roller of the feeder. Because the mechanical NC feeder needs to be equipped with auxiliary devices on the punch slider when it is installed, there are certain restrictions on the size and model of the matched punch. Because the mechanical NC feeder has a fast relaxing action, it is very suitable for short-step, high-speed processing and production occasions, as well as occasions with traditional punching machines.

In addition, in the field of thick plate stamping processing, the pneumatic NC feeder is more suitable. Because the cylinder of the pneumatic feeder not only has the relaxation function, it can also be used to clamp the material, which is tighter than the mechanical clamp, so that the thick material is not prone to slipping. Therefore, the pneumatic NC feeder is very suitable for the long and short step transportation of thick and heavy sheets and the automatic feeding of stretched products.

Figure 1-3 Punch servo feeder
Figure 1-3 Punch servo feeder

The pneumatic NC feeder has a wider application range and is easier to install and debug in the domestic stamping industry. Most of the feeder manufacturers recommend it as a standard machine to customers and the mechanical NC feeder as an option. Therefore, many stamping owners often only know that there are pneumatic models, but do not know that there are mechanical models. At the same time, mechanical NC feeders are available. The performance and adaptation of the machine are often unclear. However, the mechanical type is more suitable than the pneumatic type in many short-step, high-speed stamping occasions and with traditional punching presses.

Here are the advantages of NC servo feeder: easy to operate, just operate and set on the touch screen; wide application range, high degree of customization, high feeding accuracy, good stability, multi-stage feeding, high feeding accuracy, and can transport sheets of any length.

NC servo feeders also have their disadvantages: high cost, the cost of the servo motor used alone is much higher than that of air feeders and mechanical feeders; the feeding speed is slow, affected by the response of the servo system, and cannot meet the requirements of high-speed feeding.

How to Choose a Punch Feeder

After reading the above introduction, it is estimated that everyone has a general understanding of the types, principles, and advantages, and disadvantages of the feeder. Then how should we choose the feeder that suits our punch? Please look at the following aspects:

  • Look at the electrical configuration

The quality of the core electrical configuration of the NC servo feeder directly affects its accuracy, stability, performance, life, and failure rate. Therefore, the core electrical configuration is an important indicator to measure the quality of the CNC feeder. Electrical configuration is mainly reflected in the brands of servo motors and drives, PLC brands, touch screen sizes and brands, circuit breakers and AC contactors, etc.

  • Confirm the production status of core mechanical components

The core mechanical components of the NC servo feeder are the feed roller, bearings, gears, and timing belt wheels. The quality of these components directly affects the feeding accuracy, stability, failure rate, maintenance cost, and service life.

  • Check the manufacturer’s strength

Here we need our buyers to investigate the punch servo feeder manufacturer’s brand, market share, market user reputation, punch and mold maker evaluation, annual production capacity, production experience, manufacturer’s comprehensive after-sales strength, etc. If conditions permit, the buyer can select a few and visit the manufacturer on-site.

Figure 1-4 HARSLE punch feeder
Figure 1-4 HARSLE punch feeder
  • Test the performance of NC servo feeder

It is recommended that buyers go to the manufacturer to test the feeding accuracy, feeding speed, and feeding stability of the NC feeder. Performance is the core point of distinguishing a good machine from a bad machine.

  • Confirm whether the operation meets the requirements

When the NC servo feeder is used, it is necessary to carry out single-stroke feeding for mold trial. Therefore, not only a touch screen is required for operation, but also an operating handle is required. In addition, the height and size of the electrical box for operation also need to meet actual needs.

  • Check the technical support

Whether the manufacturer’s installation, commissioning, training guidance, and after-sales service are complete and fast. This is also very important.

When purchasing an NC servo feeder, you need to ask carefully whether the manufacturer of the feeder provides, installation, commissioning, and training instructions, and whether there is special personnel to solve the problems encountered in the later period. At the same time, strict inspections are carried out on policies and systems in terms of warranty and parts replacement.

Operation Steps

The following are the three steps of charging, feeding, and adjustment for your reference.

Figure 1-5 HARSLE punch feeder
Figure 1-5 HARSLE punch feeder

Loading

  • Make sure that all circuits, oil circuits, and gas circuits are well connected and there is no problem. Turn on the power and put the operating mode in manual mode.  
  • Press the “Rack shrink” button to minimize the rack.
  • Turn on the air pressure switch of the pressing arm, and point the arrow to “A”. At this time, the pressing arm is released.
  • Press the “trolley back” button to move the trolley back to the end.
  • Put the coil material on the trolley firmly, and then press the “trolley up” or “trolley down” button to make the center of the coil material coincide with the center of the rack as much as possible.  
  • After adjusting the center of the coil, press the “trolley forward” button to let the material rack pass through the inner circle of the coil, and make the center line of the material coincide with the center line of the straightening machine as much as possible.
  • Press the “Rack Expansion” button to allow the rack to tighten the inner circle of the coil.
  • Point the arrow of the pressing arm switch to “B”, and let the pressing wheel of the pressing arm press the outer ring of the coil.  
  • After confirming that there is no problem, return the trolley to the last end, and the loading is completed.
Figure 1-6 HARSLE punch feeder
Figure 1-6 HARSLE punch feeder

Feeding

  • Pull the eccentric and lift the handle to lift the upper roller of the leveler.  
  • Pull one end of the coil and put it between the upper and lower rollers of the leveler.  
  • Reset the eccentricity and lift the handle, and point the air pressure switch arrow of the cylinder to “B”, allowing the feed roller to press the material tightly.  
  • Set the operation mode switch on the electric control box to manual mode.  
  • Move the “leveling forward” button until the material completely extends out of the leveler.  
  • Adjust and lock the retaining wheels on both sides. The feed is complete.  

Note: The above operations must be performed in manual mode, and the buttons used above are invalid in automatic mode.

Figure 1-7 HARSLE punch feeder
Figure 1-7 HARSLE punch feeder

Adjustment 

  • When adjusting the correction effect, a piece of material about 1.5 meters long to be corrected can be used for debugging.
  • The correction effect is one of the important indicators of the correction machine. This correction machine has simplified the correction adjustment process, thus reflecting the design idea of high efficiency and low labor intensity of this machine.
  • When adjusting the leveling rollers, pay attention to the synchronization adjustment of the left and right adjustment handwheels.  
  •  After the materials to be processed are corrected to the requirements, they can be sent to the materials for automated production.

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One thought on “3 Amazing Things to Know About Punch Feeder

  1. Jack Nickson says:

    Quite interesting!
    Could you please send me the price of the NC feeder?

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