Basic Principle of Press Brake

Work scope of folding bed: It is used for bending forming of various metal rice materials such as iron, stainless steel, copper, aluminum, etc, and as a press to complete easy die forming, pressure riveting, leveling, break forming, etc. The workpiece is manufactured on LASER, NCT on cutting blanking, and in the pliers machining to produce other than bending forming pixel, and then die cutter in folding bed using folding bed or fold bed to bending forming, in addition, the convex hull, pressure pad Angle and line pressing pixel processing is usually conducted on folding bed, using fold bed die cutter and fold bed, folding bed can be finished products bending but its processing speed is slower than the punching machine, apply to the sample when bending forming and part of the bend forming and production when producing some of the bending forming

1. Working principle of folding bed

The upper and lower dies are fixed on the upper and lower worktables of the folding bed respectively, and the relative movement of the worktables is driven by hydraulic transmission, and the shape of the upper and lower dies is combined to realize the bending forming of plates.

2. Folding bed structure

Folding bed is composed of four parts :1. Mechanical part; 4. NC electrical control part; 2. Electrical part; 

3.(1) Upper moving type: the lower workbench does not move, and the upper slider is lowered to realize pressure;

(2) Downward movement: The upper machine is fixed and the lower table rises to realize pressure

4. Basic principles of bending processing sequence:

1 Bend from the inside out.

1. Bend from small to large.

1. Bend the special shape first, then bend the general shape.

1 No influence or interference will be generated after the forming of the previous process

5. Use of folding bed:

Pull convex bag, pressing foot, forming tapping bud, pressing line, printing, rivet, rivet static guide, pressing grounding symbol, drawing hole, riveting, pressing flat, triangle reinforcement, etc.

6. Basic knowledge of folding bed upper and lower molds:

1) Upper die: also known as folding knife

1 Folding bed die classification and existing tool types are shown in the following figure:

The folding bed die is divided into two types: integral type and segmented type;

Integral upper die :835mm and 415mm

Upper module of segmentation :a segmentation and B segmentation

A Segment length :10, 15, 20, 40, 50, 100 (right ear), 100 (left ear), 200, 300;

B Segment length: 10, 15, 20, 40, 50, 100 (right ear), 100 (left ear), 165, 300:

2) Lower module, also known as V slot

1 Folding bed under the mold is divided into two types: integral type and segmentation type; The integral lower die is divided into L and S(L:835mm, :415mm) : the split lower die is divided into dimensions :10, 15, 20, 40, 50, 100, 200, 400

The lower die is divided into single V and double V according to the classification of V slot

The 1V slot title is usually expressed as "slot width +V". For example, when V groove width is 5mm, the V groove is called "5V".

The width of the V groove of the lower die used by the 1 folding bed is usually 5 times of the material thickness (5T). If 5T-1V is used, the bending coefficient should be increased accordingly. If 5T+1V is used, the bending coefficient should also be decreased accordingly.

7. Folding bed after the regulation

Type: ordinary type, long double-point type, short double-point type, elongated type, gasket type, single point type, in-point position type, in-point position type.

Function:

1) Ordinary post-determination:

The face rest position is used for the end rest position of the workpiece and the left and right lateral positioning of the workpiece, the point rest position is used for the two or more rest position of the workpiece, can also be used for the one rest position (must have auxiliary facilities

2) Long and double point setting:

The small width of the workpiece is bent by the position, the common after setting, even if the backseat together, the front after setting between the 70mm gap, and with the later setting can make the front clearance reduced to 10mm: avoid burr by the position this point with the single point after setting function, but its scope of adaptation is mainly the small width by the position of the workpiece: the base surface has the function of the back setting

3) Regulation after short and double points

The basic function is the same as the long double-point post-regulation, but the scope of application is different, it can be used for the rest of shorter work pieces: suitable for NCT blanking workpiece, used to avoid burr points, to ensure the bending accuracy.

4) Lengthening after fixing

By using the lengthening characteristic, the small size or negative size of the indirect position.

After the fixed length, it can extend the machine tool 59.5 to get the rest size -59.5, which can be used for some small bending with high difficulty, indirect rest bending; The left and right positioning of the workpiece, because it is longer than the ordinary back fixing, so the workpiece in the ordinary back fixing position, it can be used as the left and right positioning of the workpiece.

5) After gasket fixing

For small size bending and leaning position, generally small size bending and leaning position need gasket, in order to avoid the upper mold is damaged after fixing, but when adding gasket, the gasket is easy to run, affecting the safe operation, from then on, the protruding part of fixing gauge will play the role of gasket, usage: the protruding part is installed downward; Large size or anti-position support workpiece against the position, bending large size, generally need two people will reach into the machine to grasp the workpiece against the position, extremely unsafe and unstable size, after the regulation can support the workpiece against the position, single person operation, use the same as above; Its base surface is the same as the common post - determiner, so it has the common post - determiner function.

6) Single point after the regulation

Used for long edge position of multi-burr surface, general NCT blanking or edge cutting products with burr points on the edge, use hereafter to fix or avoid burr points, improve the bending accuracy; It is used for the left and right positioning of the workpiece, because its base plane is the same as that of the ordinary post gauge, so the two sides of the post gauge can be mixed with the ordinary post gauge thereafter. The protrudent part can be used for the left and right positioning of the workpiece to realize the accurate hiding place between the workpiece and the mold, and the base surface has the function of the ordinary post gauge

7)After positioning of the inside point of the material, since the protruding point of the later regulation extends to another plane, it can be used for the positioning of the small square hole in the workpiece.

8) After the placement of the inner surface of the material, it shall be determined that there is a protruding structure on the upper end, which is flat with the plane of the matrix, and the width is only 1/3 of the matrix.

This point can be used for: narrow seam rest position whose width is less than the normal back gauge width; The protruding part is clamped downward, which can be used for the direct rest of the bending inside the material; Optimal range: internal bending width greater than 20 and less than 150mm; Can also be used for irregular outer edge of the small plane recluse.

Note: The general size specified thereafter is 60*9mm

Determined after the positioning of the bent when it was close to (i.e., parallel to the determined after), if cant positioning surface of the workpiece is, at this time should inspect the size of the workpiece positioning fixture, the stability of the (location) design usually L 3 to 10 mm all should consider using the positioning fixture design Yi Mo (usually) for positioning, unless special small artifacts, particularly large workpiece 10 mm, of course, the positioning of its stability is poor. As shown in the figure below:

8. Folding bed processing technology and matters needing attention

1) Bending processing scope:

The distance from the bending line to the edge is more than half of the V slot, for example, the minimum distance is 2mm if the material of 1.0mm USES the lower die of 4V. The following table shows the minimum folding edge of different material thickness:

Material thickness bending Angle 90° Bend at an Angle of 30°

Minimum flanged V groove specification Minimum folded V groove specification

0. 1 ~0.4  1.0  2 v

0.4~0.6  1.5  3V  2.2  3V

0.7 ~0.9  2.0  4V  2.5  4V 

0.9~1.0  2.5  5V  3.4  6V 

1.1~1.2  3.0  6V

1.3~1.4  3.5  7V  5.0  8v

1.5 ~ 1.6  4.0  8V

1.7 ~ 2.0  5.0  10V

2.1~2.5  6.0  12V

2.6 ~ 3.2  8.0  16V

3.3~5.0  12.5  25V

5.1 ~6.4  16.0  32V

Note: If the inner size of the edge material is smaller than the minimum edge size in the above table, the folding bed cannot be processed in the normal way. At this time, the edge can be repaired to the minimum edge size after bending, or consider the mold processing.

2)During the bending of the folding bed, due to the too small size from the hole edge to the bending line, appropriate processing must be made :

(1)LASER is used for secant treatment on the corresponding bending line.

(2)NCT is pressed on the corresponding bending line (this method is preferred).

(3) Increase the hole to the bending line (this method must be confirmed with the customer).

Note: When the hole distance close to the bending line is less than the minimum distance listed in the table, deformation will occur after bending: degree 0.6~0.8 0.9~1.0 ~1.2 1.3~1.4 1.5 ~ 1.6~2.0 2.2~2.4 Minimum distance 2.0 2.5 3.0 3.5 4.0 5.0 5.5

3) Reflexed flat:

When the convex hull is opposite to the opposite direction of the reflexure press and 2.5t away from the bending line L 3, the flattening will cause the convex hull to deform. Process treatment: Before the flattening, put a fixture under the workpiece with a thickness slightly greater than or equal to the height of the convex hull, and then use the flattening mold to flatten it.

4)When the drawing hole is too close to the bending line, it must be pressed or cut at the bending line to avoid deformation of the drawing hole during bending

5) Electroplating parts

Electroplated parts must be bent with attention to indentation and shedding of coating (special note on engineering drawings).

6) Section

The interference machining range of segment difference can be seen from the figure.

According to the forming Angle, it can be divided into straight edge and hypotenuse.

Straight edge break: when the break height h is less than 3.5 times the material thickness, the break die or easy die forming is adopted; when the height h is more than 3.5 times the material thickness, the normal one fold or two fold is adopted.

Bevel break: when the length of the bevel is less than 3.5 times of the material thickness, adopt the break die or easy die forming, and when the length is more than 3.5 times of the material thickness, adopt the normal folding of one side and one side

7) Riveting electrostatic guide rail

Folding bed riveting electrostatic guide spacing is 25. 15 mm, a riveting 15 points (the riveting punch can be unloaded, so can be single rivet riveting with interval), when the edge of the electrostatic guide rail and the bending line distance L 1 + 3 V / 2 mm (V is a folding bed lower die V groove width) can be riveting electrostatic guide first bending again, less than 1 + V / 2 mm, have to bend to riveting electrostatic guide. Such as 1.2 mm material available 5 V fold

8) Thin material with strong elasticity

Or bending Angle is very important. It is usually considered to press the line on the bending line, to open the process hole on the bending line, or to press the stiffener on the bending line, so as to avoid springback after bending, resulting in dimensional error. If the die changing is processed, the springback quantity must be considered when designing the die changing

9) Pressure convex hull

When the convex hull is easy to be molded, if the height of the convex hull is very strict, the back pressure can be considered to ensure its accuracy.

10) Folding bed pressure triangle reinforcement

Mold specifications for triangle reinforcement:

Model no. 117 107 202

Forming width (mm) 3.0 5.0 3.0 5.0 3.0 5.0 5.0

Tool width (mm) 10 20 10 20 20 10 20 10 20 10 20 10 20 20 10 20 20 10 20

The number of molds is 2 branches, 2 branches, 2 branches, 2 branches, 4 branches, 4 branches

There are two kinds of forming of triangle reinforcement :1. Sharing with bending tool at the same time, namely bending and triangle reinforcement processing at the same time

2. Press the triangle reinforcement after the workpiece is bent

Note: The number of forming triangle reinforcement is related to the number of molds. It can be seen from the above table that the same specification can be formed at most four at present. If the number is more than this, it shall be solved through negotiation with relevant personnel.