Talking about the actual evaluation of stamping die
With the increasingly fierce market competition, the replacement of automobiles is faster and faster, and the development of automobile molds is becoming more frequent and developing in a short cycle. To shorten the development cycle under the premise of ensuring the high quality of the mold, the quality and cycle of the actual mold production also play a vital role. This article mainly explains how to ensure the quality of the premise from the actual review and actual change of the stamping mold Shorten the mold development cycle.
Foam type key inspection items
Basic inspection items
First of all, it is necessary to confirm the parts and quantity of the review mold, including the upper mold, the lower mold base, the blank holder, the concave mold, the punch, the pressing core, the insert, etc., to ensure the integrity of each part, no bumps, and no defects. Secondly, confirm the correctness of the stickers, including the mold number, mold material, process, tonnage, arrow, F direction, lifting mark, etc.
For small parts such as wedge, drive block and other casting parts, the mold number, spare part number and material are pasted on a non-machined surface that is convenient for observation and does not affect processing. For the insert, in addition to pasting the mold number, material preparation number, and material, it is also necessary to determine whether to paste the margin mark according to the processing volume of the bottom surface of the insert. If the processing volume of the bottom surface of the insert is 6mm, there is no need to paste the mark; if the bottom surface is processed If the amount is 8mm or 10mm, paste “A8” or “A10” on the non-machining surface of the insert as the basis for removing the margin from the machining bottom surface, as shown in Figure 1.
In terms of strength
Check the structural strength of the working parts of the mold and the key stressed parts, such as whether the strength of the cross-cutting part of the front repair (turning) and side repairing (turning) inserts meets the mass production requirements, and whether there are bottom ribs at the stressed parts of the limit block and balance block Weight-reducing holes, whether to increase the reinforcement ribs on the opposite side guide, and whether the separate punch holder is reinforced with diagonal ribs in two vertical directions.
Chamfering
Carry out right-angle or round-corner treatment on the foam solid shape. The mold requires that the non-machined surface does not allow right angles. Right angles are not processed during the design. They need to be chamfered when the solid shape is made, and some are chamfered during machining, such as the bottom surface of the mold. ; When local machining cannot be chamfered, chamfering should be performed during manual trimming. The chamfering of the bottom surface of the mold is completed by machining to ensure that a round corner of R7mm is left after the bottom surface is processed. The back space at the cutting edge of the upper die block and the lower die scrap for casting trimming is completed by machining. In order to prevent the sharp corners of the casting from scratching the wire rope near the lifting lugs, the non-working part of the wire rope used for turning the mold and the contact path of the mold turning is rounded to R20mm, as shown in Figure 2.
Figure 1 Solid insert
Figure 2 Real lower mold and lifting lugs
Test stick
At least two test rods are required for each casting. The test rods can be designed in the lightening cavity of the casting, side, structural surface, and profile. They should be placed at an angle of 30°～60°. The distance between the two test rods should be as far as possible. The installation position of the inspection rod is more than 50mm apart from the surrounding ribs, which is convenient for manual sand burying. For molds with slides, the inspection rods must not be pasted on the slides and their side walls, and the inspection rods of the lower mold base must be drawn to avoid the full ejector rod.
Molds of different materials use different specifications of test rods. Round test rods with a diameter of 32mm and a length of 200mm are used in gray cast iron (such as FC, HT, GG, G, etc.), with a length of 200mm, a width of 50mm, and a height of 40mm. The rectangular test rods are used in ductile iron (such as GM, FCD, QT, GGG, D, etc.).
hole
The foam solid type review mainly inspects chip holes, water holes, peep holes, and threading holes. The function of chip holes is to ensure the discharge of iron chips and cutting fluid during machining. The hole size is generally set to φ40mm. The function of the water flow hole is to facilitate the outflow of the cleaning liquid during mold maintenance. The hole size is generally set to φ40mm. The function of the peep hole is to facilitate the observation of the working state of the standard part when debugging the mold, and can statically check the gap of the standard part. The peep hole is generally set as an elliptical hole with a long axis size of 60mm and a short axis size of 40mm. The function of the threading hole is to ensure the shortest distance between the sensor wires and facilitate smooth connection. The hole size is generally set to φ40mm.
Auxiliary processing
⑴V-shaped engraved line. In order to facilitate the straightening and alignment of the machining, the upper and lower mold bases and the blank holder must be marked with a 45° V-shaped groove, the groove depth is 5mm, and the groove length is 30mm.
⑵ Hundreds line. As a reference line for rough machining of the mold, this line is the line that is marked on the solid foam 100mm upwards on the basis of the bottom of the mold. Note that it does not include the amount of paste on the bottom of the mold. If it is 100mm from the bottom of the mold, the mold is suspended The location is marked in multiples of 100mm.
⑶ Three-pin reference hole. As a standard for semi-finishing and finishing of the mold, the hole size of the three-pin standard hole is φ10mm and 20mm deep.
⑷Z direction reference stage. As a datum plane in the Z direction of the processing mold, the position of the Z datum is preferentially designed in the middle of the mold, with a diameter of 50mm and a height of 10mm.
Craft leg
The process leg (Figure 3) is used as an auxiliary processing process component. Its common types are divided into three types: A, B, and C. Type A is suitable for small inserts and oblique wedge (size <800mm), and Type B is suitable for medium inserts. Oblique wedge, pressure core (800mm <size <1500mm), C type is suitable for large inserts, pressure core (size>1500mm), the size of each type is shown in Table 1.
Figure 3 Process leg
Table 1 Process leg size type
Auxiliary parts with a clamping plane do not need to make craft legs. For other situations where craft legs need to be set, the craft legs should avoid the guide plate surface, side pin surface and the position of the flip screw, and the height should be as consistent as possible.
Inserts with a size less than 350mm×350mm and the bottom surface has blocking walls, keyways, yields, and limits (Figure 4). The auxiliary parts are evenly distributed with 3 to 4 process legs. If the top is higher than the profile, the process cannot be The legs are arranged in concave shapes and corners. The crafted legs should not be attached to the blocking wall and the joint surface. The remaining inserts are not made of crafted legs.
The inserts of 350mm<size<800mm are evenly distributed with 3 to 4 process legs, and the top is higher than the profile, as shown in Figure 5.
The easy-deformable cover inserts need to be supported by anti-deformation technology to ensure that the casting deformation is controlled within the minimum range, the rough machining stability is controlled within the accuracy range, and the vibration aging completely releases its internal stress. Finally, the process support is removed, such as As shown in Figure 6.
Real change considerations
In the period from mold project development, mold drawing design completion to real mold casting, due to product design changes, process optimization adjustments or real mold changes, some changes do not need to change the foam shape, and some changes need to change the foam shape.
Figure 4 Small inlay process leg
Figure 5 Large inlay process leg
Figure 6 Cover panel insert
No need to change the shape of the foam
If the product design deformation surface change is within 5mm, the foam solid type does not need to be changed, the process parting line changes within 5mm, and the trimming line and flanging line change within 3mm do not need to change the foam solid type.
Need to change the shape of the foam
The amount of change of the product design deformation surface exceeds 5mm, and the change of the process parting line exceeds 5mm. The amount of foam solid type is required. When the amount of adhesion is based, if the molding surface and processing surface are used as the benchmark, the actual amount of adhesion needs to be changed. The influence of the scope; if the casting surface is used as the benchmark, the scope is marked and the actual amount of paste is directly carried out according to the measured size of the real shape drawing.
In addition to the molding surface, if the foam solid structure is changed, such as moving the inspection rod position, moving the feeding direction arrow, changing the inserts, and changing the foam solid structure part, pay attention to the reference datum to mark the change range and the actual size It is necessary to change the design of the mold drawing to be consistent with the actual foam drawing, to avoid mechanical processing and to avoid the subsequent changes in the drawing and the failure of the theoretical analysis in the early stage, and even the waste of cycle and cost.
Concluding remarks
After the specification of the cold stamping die review process and the change plan, the review efficiency and foam quality are improved, the mold delivery cycle is shortened, the cost is saved for mold development, and the production cycle is guaranteed.