冲压模具设计中对机械运动的控制和运用及冲压模具设计的安全要求
冲压过程存在多种多样的机械运动，而各种机械运动对冲压工艺实现与冲压件品质的影响也各不相同，因而在冲压模具设计中对机械运动的控制和灵活运用对提高设计水平和保证冲压件品质具有重要意义。
1.冲压过程中机械运动的概述
冷冲压就是将各种不同规格的板料或坯料，利用模具和冲压设备(压力机，又名冲床)对其施加压力，使之产生变形或分离，获得一定形状、尺寸和性能的零件。一般生产都是采用立式冲床，因而决定了冲压过程的主运动是上下运动，另外，还有模具与板料和模具中各结构件之间的各种相互运动。
机械运动可分为滑动、转动和滚动等三种基本运动形式，在冲压过程中都存在，但是各种运动形式的特点不同，对冲压的影响也各不相同。既然冲压过程存在如此多样的运动，在冲压模具设计中就应该对各种运动进行严格控制，以达到模具设计的要求；同时，在设计中还应当根据具体情况，灵活运用各种机械运动，以达到产品的要求。
冲压过程的主运动是上下运动，但是在模具中设计斜楔结构、转销结构、滚轴结构和旋切结构等，可以相应把主运动转化为水平运动、模具中的转动和模具中的滚动。在模具设计中这些特殊结构是比较复杂和困难，成本也较高，但是为了达到产品的形状、尺寸要求，却不失为一种有效的解决方法。
2.冲裁模具中机械运动的控制和运用
冲裁工艺的基本运动是卸料板先与板料接触并压牢，凸模下降至与板料接触并继续下降进入凹模，凸、凹模及板料产生相对运动导致板料分离，然后凸、凹模分开，卸料板把工件或废料从凸模上推落，完成冲裁运动。卸料板的运动是非常关键的，为了保证冲裁的质量，必须控制卸料板的运动，一定要让它先于凸模与板料接触，并且压料力要足够，否则冲裁件切断面质量差，尺寸精度低，平面度不良，甚至模具寿命减少。
按通常的方法设计落料冲孔模具，往往冲压后工件与废料边难以分开。在不影响工件质量的前提下，可以采用在凸凹模卸料板上增加一些凸出的限位块，以使落料冲孔运动完成后，凹模卸料板先把工件从凹模中推出，然后凸凹模卸料板再把废料也从凸凹模上推落，这样一来，工件与废料也就自然分开了
对于一些有局部凸起的较大的冲压件，可以在落料冲孔模的凹模卸料板上增加压型凸模，同时施加足够的弹簧力，以保证卸料板上压型凸模与板料接触时先使材料变形达到压型目的，再继续落料冲孔运动，往往可以减少一个工步的模具，降低成本。
有些冲孔模具的冲孔数量很多，需要很大冲压力，对冲压生产不利，甚至无足够吨位的冲床，有一个简单的方法，是采用不同长度的2～4批冲头，在冲压时让冲孔运动分时进行，可以有效地减小冲裁力。
对那些在弯曲面上有位置精度要求高的孔(例如对侧弯曲上两孔的同心度等)的冲压件，如果先冲孔再弯曲是很难达到孔位要求的，必须设计斜楔结构，在弯曲后再冲孔，利用水平方向的冲孔运动可以达到目的。对那些翻边、拉深高度要求较严需要做修边工序的，也可以采用类似的结构设计。
3.弯曲模具中机械运动的控制和运用
弯曲工艺的基本运动是卸料板先与板料接触并压死，凸模下降至与板料接触，并继续下降进入凹模，凸、凹模及板料产生相对运动，导致板料变形折弯，然后凸、凹模分开，弯曲凹模上的顶杆(或滑块)把弯曲边推出，完成弯曲运动。卸料板及顶杆的运动是非常关键的，为了保证弯曲的质量或生产效率，必须首先控制卸料板的运动，让它先于凸模与板料接触，并且压料力一定要足够，否则弯曲件尺寸精度差，平面度不良；其次，应确保顶杆力足够，以使它顺利地把弯曲件推出，否则弯曲件变形，生产效率低。对于精度要求较高的弯曲件，应特别注意一点，最好在弯曲运动中，要有一个运动死点，即所有相关结构件能够碰死。
有些工件弯曲形状较奇特，或弯曲后不能按正常方式从凹模上脱落，这时，往往需要用到斜楔结构或转销结构，例如，采用斜楔结构，可以完成小于90度或回钩式弯曲，采用转销结构可以实现圆筒件一次成型。
值得一提的是，对于有些外壳件，如电脑软驱外壳，因其弯曲边较长，弯头与板料间的滑动，在弯曲时，很容易擦出毛屑，材料镀锌层脱落，频繁抛光弯曲冲头效果也不理想。通常的做法是把弯曲冲头镀钛，提高其光洁度和耐磨性；或者在弯曲冲头R角处嵌入滚轴，把弯头与板料的弯曲滑动转化为滚动，由于滚动比滑动的摩擦力小得多，所以不容易擦伤工件。
4.拉深模具中机械运动的控制和运用
拉深工艺的基本运动是，卸料板先与板料接触并压牢，凸模下降至与板料接触，并继续下降，进入凹模，凸、凹模及板料产生相对运动，导致板料体积成形，然后凸、凹模分开，凹模滑块把工件推出，完成拉深运动。
卸料板和滑块的运动非常关键，为了保证拉深件的质量，必须控制卸料板的运动，让它先于凸模与板料接触，并且压料力要足够，否则拉深件容易起皱，甚至裂开；其次应确保凹模滑块压力足够，以保证拉深件底面的平面度。
拉深复合模设计合理，可以很好地控制结构件的运动过程，达到多工序组合的目的。例如典型的落料拉深切边冲孔复合模具的设计。
另外，有些装饰品和日用品的拉深件需要有卷边(或滚边)工序，模具设计中也用到了滚轴结构，所以在卷边过程中滚动的摩擦力非常小，不容易擦伤工件表面。
对那些需要在马达中旋转的拉深结构件,切边的高度、跳动度等要求相当高，需要在模具中设计特别的旋切结构，利用旋转(切)运动修边，不仅能保证切边的尺寸精度高，甚至切边的毛刺及冲切纹路亦相当美观。值得一提的是，此旋切结构在实际设计改良后，已经非常易于模具加工制作，并且已运用于连续拉深模具当中。
5.连续模具中机械运动的控制和运用
连续模具中常常同时包括了冲裁、弯曲和拉深等冲压工艺，因而其冲压过程中的机械运动也包括了这三种工艺的基本运动模式，对连续模具中运动的控制，应分成各基本工艺分别进行控制。
通常连续模具要求不断加快冲压速度，提高生产效率，有些形状较复杂、较特别的冲压件，其冲压运动较费时，在连续模具设计中可以分解成效率较高的冲压运动。例如，工程膨胀螺钉圆筒件在连续模具设计中即可将其圆筒成型运动分解为两侧90度圆弧弯曲～中间60度圆弧弯曲～整体抱圆～圆度校正四个工序，不仅提高效率，亦能保证冲压件圆度。
需要特别指出的是，连续模具因为在实际生产中还牵涉到送料机、吹风装置等，在设计中应充分考虑到这些因素，让冲床、模具、送料机和吹风装置的运动在时间上配合好，连续模具才能真正顺利生产。
冲压模具设计的安全要求
冲压模具是冲压加工的主要工艺装备，冲压制件就是靠上、下模具的相对运动来完成的。加工时由于上、下模具之间不断地分合，如果操作工人的手指不断进入或停留在模具闭合区，便会对其人身安全带来严重威胁。
（一）模具的主要零件、作用及安全要求
1.工作零件凸凹模是直接使坯料成形的工作零件，因此，它是模具上的关键零件。凸凹模不但精密而且复杂，它应满足如下要求：（1）应有足够的强度，不能在冲压过程中断裂或破坏；（2）对其材料及热处理应有适当要求，防止硬度太高而脆裂。
2.定位零件定位零件是确定坯件安装位置的零件，有定位销（板）、挡料销（板）、导正销、导料板、定距侧刀、侧压器等。设计定位零件时应考虑操作方便，不应有过定位，位置要便于观察，最好采用前推定位、外廓定位和导正销定位等。
3.压料、卸料及出料零件压料零件有压边圈、压料板等。
压边圈可对拉延坯料加压边力，从而防止坯料在切向压力的作用下拱起而形成皱褶。压料板的作用是防止坯料移动和弹跳。顶出器、卸料板的作用是便于出件和清理废料。它们由弹簧、橡胶和设备上的气垫推杆支撑，可上下运动，顶出件设计时应具有足够的顶出力，运动要有限位。卸料板应尽量缩小闭合区域或在操作位置上铣出空手槽。暴露的卸料板的四周应设有防护板，防止手指伸入或异物进入，外露表面棱角应倒钝。
4.导向零件导柱和导套是应用最广泛的一种导向零件。其作用是保证凸凹模在冲压工作时有精确的配合间隙。因此，导柱、导套的间隙应小于冲裁间隙。导柱设在下模座，要保证在冲程下死点时，导柱的上端面在上模板顶面以上最少5至10毫米。导柱应安排在远离模块和压料板的部位，使操作者的手臂不用越过导柱送取料。
5.支承及夹持零件它包括上下模板、模柄、凸凹模固定板、垫板、限位器等。上下模板是冲模的基础零件，其他各种零件都分别安装固定在上面。模板的平面尺寸，尤其是前后方向应与制件相适应，过大或过小均不利于操作。
有些模具（落料、冲孔类模具）为了出件方便，需在模架下设垫板。这时垫板最好与模板之间用螺钉连接在一起，两垫板的厚度应绝对相等。垫板的间距以能出件为准，不要太大，以免模板断裂。
6.紧固零件它包括螺钉、螺母、弹簧、柱销、垫圈等，一般都采用标准件。冲压模具的标准件用量较多，设计选用时应保证紧固和弹性顶出的需要，避免紧固件暴露在表面操作位置上，防止碰伤人手和妨碍操作。
（二）模具设计的安全要点
在结构上应尽量保证进料、定料、出件、清理废料的方便。对于小型零件的加工要严禁操作者的手指、手腕或身体的其他部位伸入模区作业；对于大型零件的加工，若操作者必须手入模内作业时，要尽可能减少入模的范围，尽可能缩短身体某部位在模内停留的时间，并应明确模具危险区范围，配备必要的防护措施和装置。
模具上的各种零件应有足够的强度及刚度，防止使用过程中损坏和变形，紧固零件要有防松动措施，避免意外伤害操作者。
不允许在加工过程中发生废料或工件飞弹现象，影响操作者的注意力，甚至击伤操作者。另外要避免冲裁件毛刺割伤人手。不允许操作者在进行冲压操作时有过大的动作幅度，避免出现使身体失去稳定的姿势；不允许在作业时有过多和过难的动作。应尽量避免冲压加工时有强烈的噪声和振动。模具设计应在总图上标明模具重量，便于安装，保障安全。20千克以上的零件加工应有起重搬运措施，减轻劳动强度。装拆模具零件时应方便安全，避免有夹手、割手的可能；模具要便于解体存放。总之，模具中的哪怕是细微的问题都会影响安全，只有对每种作业中的具体问题进行分析，才能提出模具中的安全注意事项。
Stamping mould design of mechanical motion control and use and stamping mould design safety requirements
Stamping process is variety of mechanical motion, and all kinds of mechanical motion, stamping process to realize and stamping quality effect is different, so the stamping mould design of mechanical motion control and flexible application for raising the design level and ensure stamping quality to have the important meaning.
1. The stamping process an overview of mechanical motion
Cold stamping is of different specifications will be in the process of sheet metal or blank mould and stamping equipment, use (press, another name to pressure the punch), the deformation or separation, access to certain shape, size and performance of the parts. General production is the vertical punch, and decided the main movement of stamping process is up and down movement, in addition, there is the sheet metal mold and die in the structure of all kinds of mutual movement between.
Mechanical motion can be divided into sliding, the rotation and rolling, three basic forms of exercise in stamping process, there are various forms of exercise, but the different characteristics, the influence of the stamping is different. Since stamping process is so diverse movement and in stamping mould design for all kinds of sports should be strict control, in order to achieve the mould design requirements; At the same time, in a design should also according to the specific circumstances, make use of various mechanical motion, in order to achieve the requirements of the product.
Stamping process is main movement up and down movement, but in the mold of inclined wedge design structure, structure, structure and presenting roller rotary cutting structure etc, can the corresponding main movement into level sports, of die and mould rotation of the scroll. In the mold design of these special structure is more complex and difficult, costs are high, but in order to achieve a product's shape, size requirement, but is a good solution.
2. In the die cutting mechanical movement control and use
Cutting craft basic motion is unloading board first contact and sheet metal press a prison, the punch down to the sheet metal contact and continue to fall into the concave die, convex, concave die and relative motion sheet metal sheet to separate, then convex, concave die separate, unloading board the piece or waste from the punch, and complete the lagging on cutting movement. The movement of unloading board is critical, in order to ensure the quality of the cutting, must control the movement of unloading board, make it before the punch and sheet metal contact, and the material force should be enough, or cutting a cut area poor quality, low dimensional accuracy, flatness bad, and even die life is reduced.
According to the common method of design blanking punching die, often after stamping workpiece and waste to separate edge. No impact on the premise of workpiece quality, can use in die and punch unloading board adding some protruding set blocks, in order to make blanking punching movement, concave die after the completion of the unloading board first the piece out from the concave die, and die and punch unloading board again from the waste die and punch. So, lagging the workpiece and waste natural separated
For some of the larger local convex stamping, can be in blanking punching die of concave die unloading board type pressure of the punch, and at the same time put enough spring force, in order to ensure that the unloading board pressed the punch and sheet metal contact material deformation are first to pressed purpose, continue to blanking punching, often can reduce sports a work of mold, reduce cost step.
Some punching mould punching number, need very blunt, stamping production negative pressure, and even without enough tonnage of punch, has a simple method, it is to use different lengths of 2 ~ 4 batch of punch in stamping, let punching movement points, and can be effectively reduced cutting force.
For those in bending surface position precision of the high demand of the hole (such as the two aperture concentricity bending, etc.) of the stamping, if the first bend is difficult to meet again punch a hole requirements, must design the structure of the bending, wedge again after the utilization level of direction, punching punching movement can achieve a goal. For those who turn over the side, deep drawing height stricter requirements need to do trimming process, also can with similar structure design.
3. Of bending die mechanical movement control and use
Bending process basic motion is unloading board first and sheet metal contact and killed, the punch down to the sheet metal contact, and continue to fall into the concave die, convex, concave die and relative motion in sheet metal, sheet metal bending deformation, and then convex, concave die bending concave die apart, on top of the stem (or the slider) to launch, complete edge bending bending movement. Unloading board and top of the stem movement is a key, in order to guarantee the quality of the bending or production efficiency, must first control the movement of unloading board, let it before the punch and sheet metal contact, and the material force must be enough, or bend a size accuracy is poor, poor plane degree; Second, shall ensure that top stem force enough, to make it successfully launched the bending parts, or bend a deformation, the production efficiency is low. For higher accuracy bending part, should pay special attention to a little, best in bending movement, want to have a movement, that all relevant parts dead spots can touch death.
Some of the more exotic, or bend shape after bending according to normal way not from concave die off, at this time, often need to use the wedge structure or structures, such as by presenting, inclined wedge structure, can complete less than 90 degrees or back to hook type bending, presenting the structure can realize a forming a cylinder.
Be worth what carry is, for some shell parts, such as computer floppy drive enclosure, because of its bending side is longer, elbow and between the sheet metal bending, sliding, in very easy to wipe out soft flocks, materials galvanized layer falls off, frequent polishing curved punch effect is not ideal. It is usually the bending the punch of titanium coating, and improve the finish and wear resistance; Or in bending the punch R Angle place the elbow and embedded roller, sheet metal bending sliding into rolling, because than sliding friction small roll, so not easy scratches workpiece.
4. In deep drawing mould mechanical movement control and use
Deep drawing technology basic motion is unloading plate, sheet metal contact and first and press a prison, the punch down to the sheet metal contact, and continue to fall into the concave die, convex, concave die and relative motion in sheet metal sheet metal forming, volume, and then convex, concave die separate, concave die slider launched the piece, complete deep drawing movement.
Unloading board and the slider sport very key, in order to guarantee the quality of the drawing parts, must control the movement of unloading board, let it before the punch and sheet metal contact, and the material is enough to force, or drawing parts easy corrugate, even opened; Second shall ensure that concave die slide block enough pressure, in order to ensure that the drawing parts the underside of the flatness.
Deep drawing composite modulus reasonable design, can be a very good control structure motion process, to achieve the purpose of combination process. For example the typical blanking pull deep side punching compound mould design.
In addition, some decorations and necessities of drawing parts need to have edge (or roll) process, the mold design of roller structure with, so in the edge of the rolling friction in the process is very small, not easy to scratch the surface.
For those who need in the motor rotation in the deep drawing parts, the height of the machine, beating degree requirements quite high, and need in the mould design of special rotary cutting structure, rotating (cut) movement trimming, can not only ensure the size of the machine, high precision, even the burr and cutting machine, it was a beautiful lines. Be worth what carry is, the rotary cutting structure in actual design improvement, have very easy to mould processing production, and have been using concrete continuous deep drawing of mould.
5. Mould continuous mechanical movement control and use
Continuous often die and includes cutting, bending and deep drawing, and etc, so the stamping process in the process of stamping mechanical motion also includes the three kinds of craft basic sports mode, in the mold of continuous motion control, and shall be divided into the basic process control respectively.
Usually required for accelerating speed stamping mould, improve the production efficiency, and some shape is more complex, more special stamping, the more time-consuming stamping movement, in the mold design of continuous can be decomposed into higher efficiency of stamping movement. For example, engineering expansion in a continuous screw cylinder mold design of the cylinder molding movement can be broken down into two side 90 degrees arc bending ~ 60 degree among the whole arc bending ~ ~ roundness correction arms round four process, not only improve efficiency, also can guarantee the stamping roundness.
It must be pointed out that continuous mold because in practical production also involves tape feeder, hair drier device etc, should be considered in the design to these factors, let the punch and die, tape feeder and blow dry device in time with the movement, continuous mould can really smooth production.
Stamping mould design safety requirements
Stamping die is the main technological equipment stamping processing, stamping parts, under which is on the relative motion of the mold to finish. Because, under the processing mould constantly points between close, if the operator fingers are coming in the mold or stay closed area, will be to their personal safety brought serious threats.
(a) the main parts, mould role and safety requirements
1. Work parts die and punch is directly to the work of blank forming parts, therefore, it is the key parts of the mold. Die and punch precision and complex, it not only should meet the following requirements: (1) should have enough strength in stamping process, can't break or destruction; (2) the proper material and heat treatment requirements, prevent hardness is too high and crisp crack.
2. Positioning parts is to determine the ware positioning parts installation position parts, have pins (board), to block material pin (board), collaborations pin, guide material board, spacer side knife, side pressure gauges, etc. Design positioning parts should be considered when convenient operation, there should be a location, location to for observation, had better use the presumption, and a former profile positioning and guide is positioning pin.
3. Pressure material, unloading the material and parts pressure parts material blank-holder, pressure plate, etc. Material
Blank holders can pull out of the blank holder force pressure, so as to prevent the blank tangential pressure under the function of arches and the formation of a ruffle. The role of the disc pressure is to prevent blank mobile and bounce. The top out, unloaded board's role is to facilitate a and clean up waste. By the spring, they rubber and equipments of the push rod, air cushion support movement up and down, top, a design should have enough top sports will have a limited, the output. Unloading board should be closed area or narrow as far as possible in operating location mill out an empty tank. Exposed unloading around the board should have protection board, prevent a finger into the or foreign body in surface, exposed edges should fall blunt.
4. Orientation guide post and guide set parts is one of the most widely applied a guide parts. Its role is to guarantee the stamping die and punch in the job, with accurate fitting clearance. Therefore, guide pin, guide of clearance should be focusing cutting clearance small. Guide pin in the mold base, to ensure that the dead spots in stroke, guide pin on in the face of the top surface above template minimum of 5 to 10 mm. The column should be arranged in a far away from the module and pressure plate material, the position of the arm not make handlers over guide pin to take material.
5. Supporting and clamping parts including template, die and it handles, die and punch fixed plate, plate, limit machine etc. Up and down is the foundation of the template stamping parts, and various other components installed fixed on it. Respectively Template of the plane, especially the size and direction should adapt to parts, too large and too small or were detrimental to the operation.
Some die (blanking, punching mould) of a convenient, need to die under the plate rack in. Then pad with best template with bolt connection between together, and two pad should be equal to the thickness of the absolute. Pad spacing can prevail in a not too big, lest the template fracture.
6. Tighten parts it including bolts, nuts, spring, column pin, washer and so on, typically use the standard parts. Stamping mould design, selection of standard amount more should guarantee the fastening and elastic ejector needs, avoid fasteners exposed to surface operating position to prevent touch hands and prevent operation. Cut
(2) die design safety issues
On the structure should try to ensure incoming material, and set the material, a clear, the convenience of waste. For the small parts processing to the operator fingers, wrists are strictly prohibited or other parts of the body stretch into die area homework; For large parts processing, if the operator must hand into the mould homework, as far as possible to reduce the scope of the mould, shorten the body as far as possible a bit in the mould, and the time duration of the mould should be clear about the danger zone range, equipped with necessary protective measures and device.
Various parts of the mold should have enough strength and stiffness in use process, prevent damage and deformation, fastening parts to has the loose measures to avoid accident harm the operator.
Don't allow in the machining process happens waste or workpiece missile, the influence of the operator phenomenon attention and wounded by the operator. In addition to avoid cutting a burr cut hands. Don't allow the operator in stamping operation is too big action range, avoid make body lose stability posture; Not allowed to have too much in the assignments and difficult movements. Should try to avoid a strong stamping processing noise and vibration. Mould design should be marked in the assembly drawing mould weight, convenient in installation, ensure the safety. 20 kg of parts processing should be lifting handling measures, reduce labor intensity. Installation mould parts should be convenient when safety and avoid a clip, cut and of the hands of the hand may; Mould to facilitate storage disintegration. In short, the mould are subtle problems even will affect the safety of each homework, only the specific problem analysis, which can be put in the mould safe.
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