1.What impact does the material feeding accuracy have?
Pay attention to the placement of guide pins: Guide pins must be installed at each station, especially before important forming stations. Absolute accuracy cannot be guaranteed by the feeder alone; secondary precision positioning must be achieved by guide pins mounted on the mold. Guide pins with tapered or spherical heads should be preferred to facilitate smooth insertion into the pre-punching holes.
Control feed angle and deformation: If the part shape is complex (e.g., with bends), attention needs to be paid to the angle increment design during continuous rolling (forming). Inappropriate increments can lead to uneven deformation, affecting the curvature of the finished product, and even causing uncontrolled springback. For complex closed-section products, the deformation coordination between stations must be considered to ensure a smooth material transition.
2.How to eliminate internal stress interference?
Reserve a "stress relief" station: During large-scale stretching or severe deformation, significant internal stress will be generated within the material. It is not recommended to complete the entire deformation in one station; instead, it should be broken down into multiple stations for gradual forming. "Shaping" or "leveling" stations should be set up after critical stations to eliminate dimensional distortion caused by stress relief.
Pay attention to carrier and connecting bridge design: The carrier is the "lifeline" for transporting the strip in the mold. The design must ensure that the carrier has sufficient strength to prevent distortion or breakage due to excessive forming force. For high-strength steel cold-rolled coils, the carrier width needs to be appropriately increased.
3.What are the effects of mold clearance and wear?
Dynamic monitoring of die temperature: During high-speed production with a progressive die, the die temperature rises significantly, leading to thermal expansion. This causes the punch to coarsen and the die hole to shrink, resulting in a reduced actual clearance and a sharp increase in friction, which can easily cause surface roughening or even jamming of cold-rolled coils. It is recommended to monitor die temperature at high-load stations (such as stretching and cold forging), and use a die temperature controller if necessary.
Layered maintenance of cutting edges: The sharpness of the cutting edges at the blanking station is crucial. If excessive burrs are found (usually exceeding 10% of the material thickness), they should be sharpened immediately. Note that uneven blanking clearance can cause additional bending moments when the material breaks, causing strip warping and affecting subsequent feeding height.
4.What are the effects of lubrication and cleanliness?
Precision Lubrication System: A micro-volume lubricating oil spraying system is recommended, precisely spraying oil onto key forming stations (stretching, flanging). It's crucial to ensure a sufficient oil film to prevent scratches while avoiding excessive oil that could cause slippage within the die or make cleaning difficult.
Effective Chip Removal and Air Blowing: Small iron chips generated during stamping are the biggest "killer" of progressive dies. A reasonable air blowing angle and dust extraction device must be designed to ensure that waste chips do not remain on the die surface or are carried to the next station. For precision-stamped cold-rolled coils, due to the high proportion of bright bands in the cross-section, the powdery fine iron chips generated during shearing are more likely to adhere to the die, requiring special attention.
5.How to monitor and protect it?
Install misfeed detection devices: Install contact or photoelectric misfeed detectors at critical locations (such as guide pin holes and side trimming stations). Stop the machine immediately if material is not fed in correctly or the strip is lifted.
Scrap blockage detection: Check if the scrap material in the lower die falls smoothly. Small scrap holes are prone to blockage, leading to die cracking.