第二章 冲裁模的结构与设计

一、课题:Task

第二章冲裁模的结构与设计

Chapter Two Blanking die’s structure and design

二、目的要求:Intention and request

1．掌握了解冲裁模的冲裁工艺及基本知识。

2．清楚了解冲裁过程分析并能够掌握冲裁件的质量分析。

3．掌握冲裁间隙的计算、分析及应用。

三、重点、难点和突破的方法: Important points、difficulty points and breach methods

冲裁工艺。Blanking technique.

典型冲裁模结构。Typical blanking die’s constructer.

冲裁模主要零部件的结构分析与标准的选用。The constructer analysis and standards’ selection of blanking die’s important components.

冲裁模设计要点the important points of blanking die’s design.

四、复习提问：Review and question

1、模具间隙正常时，金属板料的冲裁变形过程大致可分为哪三个变形阶

段？Where has 3 phases the metal sheet matal’s blanking distortion

procedure，when the mould gap is normal.

2、在正常的冲裁工作条件下，冲裁件断面具有哪四个明显特征区？

Where has four evident earmark zone’s blanking piece’s sever, At the normal conditions of blanking work.

五、教具：Teaching aid

多媒体multimedia

六、作业：Homework

习题2.1 Exercise 2.1

七、授课讲义：Classroom teaching

第二章冲裁模的结构与设计

Chapter Two Blanking die’s structure and design 使板料分离的冲压工艺称为冲裁。

The stamping technique to divide the sheet matal is called blanking. There are various kinds of it.such as, cut down, punch,pierce, trim, incise, dissect and so on.

冲裁工艺的种类很多，常用的有切断、落料、冲孔、切边、切口、剖切等。Cut、Blanking、Punch、Cutting edge、Slitting and so on。

冲裁是冲压工艺的最基本工序之一。blanking is one basic procedure of stamping technique。在冲压加工中应用极广。它既可以直接冲出成品零件，也可以作为弯曲、拉深和挤压等其它工序的坯料，还可以在已成形的工件上进行再加工（切边、切口、冲孔等工序）。

2．1 冲裁工艺Blanking technique.

2．1．1 冲裁基本知识the basic knowledge of Blanking 在冲裁工艺中，以落料、冲孔应用最多。The most use of it is punching and piercing.从板料上冲下所需形状的工件（或毛坯）称为落料。Run into the required type’s wo rk piece from the sheet matal (or roughcast) is punching.在工件上冲出所需形状的孔（冲去的为废料）称为冲孔。Run into the required form’s work piece ( the washed thing is scrap ) is pierce落料和冲孔的变形性质完全相同，但在进行模具工作部分设计时，要分开加以考虑。Punching and pierce have the same

distortion feature , but when doing the model work design , we should distinguish them to consider them

根据冲裁变形机理的不同，冲裁工艺可以分为普通冲裁和精密冲裁两大类。According to the different distortion mechanism, blanking technique has two types are common blanking and exact blanking .

普通冲裁: common blanking

是由凸、凹模刃口之间产生剪裂缝的形式实现板料分离。To make the edge of the male die and female die produce the shearing cranny to separate the sheet matal .

精密冲裁: exact blanking

是以变形的形式实现板料的分离。Through the distortion form to finish the sheet matal .

前者冲出的工件断面比较粗糙，精度较低。后者冲出的工件不但断面比较光洁而且精度也较高，但需要有专门的精冲设备及精冲模具。The former’s workpiece’s shearing surface is more rough, and the latter is more glabrous and the precision is higher, but it needs special precise equipment and model.

2．1．2 冲裁过程分析 the procedure analysis of blanking 凸模1与凹模2具有与工件轮廓一样的刃口。Male die 1 and female die 2 have the same edge with work profile. 凸、凹模之间存在一定的间隙。Male die and female die must existence gap.当压力机滑块把凸模推下时，便将放在凸、凹模中间的板料冲裁成所

需的工件。

当模具间隙正常时，金属板料的冲裁变形过程大致可分为三个变形阶段. When the mould gap is norma l,the metal sheet matal’s blanking distortion procedure has 3 phases.

（1）弹性变形阶段elastic distortion phase

（2）塑性变形阶段plastic distortion phase

（3）剪裂阶段shearing crack phase

如下图:

（1）弹性变形阶段elastic distortion phase

当凸模开始接触板料并下压时，凸模与凹模刃口周围的板料产生应力集中现象，使材料产生弹性压缩、弯曲、拉伸等复杂的变形。When the male die starts to touch with sheet matal and press it lowly,the sheet matal which around the male die and female die’s edge produce the stress central phenomena, make the material produce the elastic compression ,bend, extend and so on these complex distortion. 板料略有挤入凹模洞口的现象。此时，凸模下的材料略有弯曲，凹模上的材料则向上翘。间隙愈大，弯曲和上翘愈严重。随着凸模继续压入，直到材料内的应力达到弹性极限。

（2）塑性变形阶段plastic distortion phase

当凸模继续压入，板料内的应力达到屈服点，板料与凸模和凹模的接触处产生塑性剪切变形。When the male die is gone on pressfitting, the stress in the sheet metal will get to the yield point, and the tangency place of sheet metal and male die with cavity plate will have plastic sheer deformation.随着凸模的下压，应力不断加大，直到分离变形区的应力达到抗剪强度，塑性变形阶段结束。With the male die being pressed down, the stress goes on aggrandizing. The plastic sheer deformation place won’t be finished with separate deformed zone of stress gets to the shearing strength.

（3）剪裂阶段shearing crack phase

当板料的应力达到抗剪强度后，凸模再向下压，则在板料与凸模和凹模的刃口接触处分别产生裂纹。After sheet matal stress gets to the shearing intension, the male die is gone on being pressed down and the fissure will be begot at the tangency place of sheet metal and male die’s with cavity plate’s blade mouth apart . 随着凸模下压，裂纹逐渐扩大并向材料内延伸。With the male die being pressed down, fissure is come to enlarge and extended to the inside of materials.

当上、下裂纹重合时，板料便被分离。When surfissrue and lay-fissure coinage, sheet matal will be asundered .

凸模再下压，将已分离的材料克服摩擦阻力从板料中推出，完成冲裁过程。And with male die being frictional ressistance and will be pushed out of the sheet matal and then the blanking course will be finished.

在正常的冲裁工作条件下，由凸模刃口出发的剪裂缝与由凹模刃口出发的剪裂缝是重合的。这时可以得到如图2.4所示的冲裁件断面，它具有明显的四个特征区。At the normal conditions of blanking work, the shear fracture slots are coinage, which start off the male die and cavity plate blade mouth.Now, the blanking piece’s sever panel is being obtainde.Look at the picture 2-4.It has four evident earmark zone’s.

（1）圆角带；circle angle zone

（2）光亮带；euphotic zone

（3）断裂带；fracture zone

（4）毛刺。burr

2．1．3 冲裁件的质量分析 blan king piece’s quality analysis

1．尺寸精度；size precision

2．断面质量；breaking surface’s quality

3．毛刺。burr

2．1．4 冲裁间隙blanking gap

冲裁间隙是指冲裁凸模和凹模之间工作部分的尺寸之差。如图

2.6所示，即blanking gap is the difference size between the male

die and female die’s work part. Look at the pi cture2.6.?

Z＝ D凹一D凸?如无特殊说明，冲裁间隙一般是指双边间隙。If

it has not other special illustration, blanking gap is the bilateral gap.

小结：

本次课主要讲述了冲裁基本知识（the basic knowledge of Blanking），冲裁过程分析（the procedure analysis of blanking），冲裁间隙blanking gap。重点是（Important points）冲裁间隙blanking gap。