How to Choose A Right Power Press

When choosing a power press, you must leary understand the purpos of its use. Fully understanding the processing methods, working methods, functions of punching machines, technical trends, etc. However the processing method and the function of the press are very complicated and dificult to understand. The wronc coic of pes mchie illead to areduction in the efficiency of the press and may result in waste of equipment investment and other results.

There are three main tips of punching capacity:

1. Pressure cacity refrs to the positiono the lider at thebottom dead center in mm, wich can produce a to o prsue. Ths presure is also called "minal ressure" or capaity" for short, and the unit is expressed in tons.
       2. Toraue capait: refers to the position where the pressure capability is generated. Tht is the distance above th botom ded cet, hichis also caled the "capablty generation pon.and the unit is expressed in mm.
       3. Working capacity: refers to the maximum effective capacity that can be produced during one-stroke processing, and the unit is expressed in ka-m.

How to choose the right press?

1. Correctly determine the processing method and operation method:

(1) Correctly determine the processing method and engineeringThere are various methods for stampinq, sometimes in combination with cutting. When selecting a punch, you should first check whether the desired processing method isapropriate for te target product and the appropriate number of processing projects. If the processing method is decided, the type of punch that should be selected is roughly determined.

(2) Degree of productionIf a batch exceds 3000-500, t is more advantageous to use automati feeding. When there are many projects and there is a large amount of production, it is necesay to consider the use of continuous processing and transfer processing, and also to review the automatic machinery such as high-speed automatic punching machines and transfer punching machines. The choice of general-purpose punching machine or automatic punching machine is mainly determined by the amount of producion, but basically the necessary amount should be considered. and the appropriate inventory should be maintained frequently, and not only for the present but also for the future production market. Situation, technical trends, etc.. 

(3) The relationship between the shape, quality and size of the materialThe shape and quality of the material should be determinedi relation to the procesing etod,utizatin ate, and aterial tliation ate. Th shape of the material depends on any one of the coiled materials, fixed-lenath material or semi-processed product, and its size, and its operation method is also very differen

(4) How to supply materials, take out products, and dispose of wasteThe above operations are colletively referred to as materil handling (MATERIAL HANDLING). In the producion plat in theal-round operation, material handing accounts for a large proportion. Therefore, material processing is not just a patial digestion of production. but must be considered from the rationlization of the factory as a wole. Accordina to the matrial handling considerations, the functions required in the stamping machinery are very differen

(5) How to use the die buffer (DIE CUSHION)During the extensin process, addional die buffers shoud be cnsidered in the sigle-action punch. Due to the hig eroman e ete ie re i posbl to peror di fiult draing operations without using a double-action punch. The auxiliary device to improve the performance of the die buffer requires a locking device.

2. Select the punching capacity suitable for processing

(1) Calculate the processing pressure and processing pressure stroke curveThe maximum pessure required during processing and the pressure change during the processin stroke shoul be clated.For multi-engineering processing, the pressure stoke curve of each project should be obtained, and the combined pressure stroke curve should be obtained by overlapping. Determine the maximum pressure and pressue sroke curve of the process tos determine the pressure capacity that should be selectes for the decision of working ablity, the frequency of processing should be decided first (processing several times per minute). The horsepower of the punching machine equipped with thel autonatic feeding device is preferably a motor with an increase of one horsepower tis best not to choose the cacity of the punch just for the capacity of the press, but to select a puncl with a commonly used capacity of 7580% of the nominal capacity.

(2) Eccentric load. degree of concentrated loadOf course, when one punch press is used with more than two dies or when a continuous die is used, there is of course an eccentic load, but most of the punching processes also have an eccentric load. Because the design of stamping capacity is usually based on the center load, it must be noted that the pressure capacity will decrease when there is an eccentric load.Therefore, for the operation of eccentric load, the punching capacity with sufficient marain should be selected. Most cold foraing processes are extremely concentrated loads. Fol concentrated load operations, try to select a punch with a small die space.

(3) Calculate the reduction of the effective capacity of the die bufferWhen thede bufer is istalled, h rawin aity o he punh s equal o te abilit o educt he bufr Geraly, the aity he ufer /6 f he nominal capacti f he punch ress. This value sems ob vey all t frst iht, t ti is dfitiln ot low vau u ut a apropratevalue n the vit o th m ipoin f the pnh fi i ompare withe efecive rawing capacity available for drawing processingAlthough the high bufferin capacity of 13 of the punching capacity is taken due to processing needs, in the case of a standard punching machine, the effective extension capacitynear thel midpoint of the stroke will be significantly reduced (in extreme cases, the ability to push the buffer will be lost). So pay more attention.Therefore, for such high buffering capacity, the toqe cacity of the reshould also be seleced to be higher If he bufering apacit is aies to hih it iwill become an unecomical structure due to the mismatch of torque capacity, so when it is necessary, it is better to consider using a double-acting punch.

3. Defining the dimensional accuracy of processed productsThe necessary accuracy of the processed product is determined by the use of the product and its connection with the next project. In the actual stamping procs, the thikness of the material, the volume of the blank block (during extrusion processing, the material (elated to the deformation resistance) and the degree of lubrication, etc, and the wear of the mold as the production progresses There are many reasons for poor machining accuracy.

4. Fully understand the function of the punch

(1) Fully investigate the specifications of the punch catalogThe catalog specificaions indicate the main capabilities and sizes of the punch presses and are the basis for selecting the punch presses. The expression of punching capacity usually onl indicates the pressure capacity, and the torque capacity and working capacity should be combined for review. The punching machine for blanking should shorten the stroke and increase the SP of this part. Suchas te heicht of the die, the width o the workn surace, theT-rove of the workin urfae of he die the buferp n hle,etc ut e etemined in concection witi the die used.It should be noted that the excessive requirements on the specifications of the punch press due to the limitations of the plant have a negative impact on the function of the punch pres.Therefore, if there is no problem in the specifications, you should choose a standard-size press, and a press with stable functions and good result

(2) Selection of attachments for punchAppropriate use of accessory devices can increase productivity. so various accessory devices should also be fully reviewed.In order to increase production the best method is to use an automatic feeding device for continuous processing. If the work such as the supply of materials and the removal of products is toc complicated and continuous processing is difficult. a timer (TIMER) can be used for continuous operation within a limited time to improve production efficiency.The use of conveyor or unloader (UNLOADER) device is also beneficial to improve productivity. For example, when changing the mold frequentl, the quick mold exchange (Q.D.C) devio and the die fixture are also beneficial. Can consider slow running device, material replacement, product stacking device, etc. The stampin shall be equipped with stepless speed change device with roller feeding. And should take into account the future need to prepare the device buffer and feeder (EE) or rotary cam (ROTARYCAM). However, if too many complicatec attachments are equipped. the failure rate will be increased, and the maintenance trouble will be increased. Therefore, the punch attachments must be properly selected.

(3) The flexibility of relevant functions should be reviewecIn order to maintain a aood utization rate, the function of the punching machine must meet the market trend of fierce model replacement. That is, we should review the functions that can be dapted to both mass production and small production, as wll as the functions that can be followed in the future mdel replacement. For exape,in orde to failiate snchronization. the driving power of the automatic feedin device is usually taken from the crank shaft of the punch. In this way, it will become a punch with an automatic feeding device and enhance the specificity of a certain operation

lf a separate drive feeder is used, because of its independent power, it can be easily moved, can be freely combined with any punch, and can respond to changes in operations.

(4) Choose a punch that is easy to maintain and has high reliablityDue to the large production volume and the usually need for several engineering operations, stamping products have a gretimact on the oveall production if they are shut down due to the failure of the punch press. Therefore, you should choose a punch that is easy t maintin inspect, anaha hieh elalilt epcily the sabilit nd urbility o the luch brake and.electrical operation relationship).

(5) SecurityStamping operations are operations with a hich risk of disasters. so full consideration shoud be aiven to safety countermeasures. When selecting a punching machine, one with a safety equipment function should also be selected. There will be no accidents when there is an erroneous operation, and the operation can be performed safely. Therefore, the operation of the punching machine should have various interlock devices, shearing type and hydraulic overload safety devices. two-handed operation. light tpe mechanical type and othe safety devices foroperation.

(6) Noise and vibratiorThe noise and vibration of stamping factories are restriced by laws and regulations due to poluion problems. The operatig enviromet i an impota s su in the fure. Therfr, it is necessarv to incorporate noise and vibration countermeasures into the stamping equioment in the future.