Optimization control of process loss assessment
(1) Control of the amount to be removed from the head and tail of the roll. To optimize the packaging solution for coil materials in response to the risks of cleanliness and appearance degradation, green anti-rust film, white waterproof film and winding film are used for aluminum coil packaging. For the binding tape printing, use the specified plastic steel tape, with corner guards and guard plates on the inner and outer edges, and protective panels at both ends of the coil material to prevent potential transportation injuries to the aluminum coil. The opening Angle of the wooden bracket is matched with the roll weight setting to ensure that the binding is firm. As it is a surface contact rather than a non-linear contact, the upper surface of the bracket is pasted with anti-squeezing felt or rubber pads to reduce transportation injuries caused by vibration during long-distance transportation.
At the material head shear, the outer circle is gradually cut off one circle at the set step distance (generally 300 to 600mm), and then the quality inspection personnel check the quality of the rolled plate. If it meets the requirements, no additional cutting is required. The tail material section is set by the program. The last two turns are cut at the material head without passing through the line body. From the third to last picture, it passes through the line body. The part that is really unusable is thrown into the tail waste box of the line. Through the optimization of the original coil incoming material and the control of on-site operation.
(2) Adjustment of roll width tolerance. The positive tolerance for the delivery of coil materials (0 to 3mm for coil widnesses not exceeding 2000mm and 0 to 5mm for those exceeding 2000mm) shall be uniformly standardized to a symmetrical tolerance of ±1.5mm.
(3) Process inspection differentiation definition. For inner and outer plates, in combination with the delivery standards of sheet materials and the characteristics of parts, prepare the appearance sealing samples for each type of sheet material. Conduct joint review and co-signature on the uncoiling line/stamping line/quality/process/material, and customize the external release standards and production standards for different sheet materials in a personalized manner (for example, inner plate parts or structural parts without hand feel scratches can be released) Minor scratches within 100mm from the edge of the outer plate or in the waste area that can be removed during the stamping and trimming process on the non-product surface can be released. Once the sample sealing standards are met, it can be delivered and produced. This avoids a one-size-fits-all approach and also prevents different reviewers from giving different opinions due to their different understandings of the standards. For irregular-shaped sheet materials and large and small materials, sign the appearance seal sample and size seal sample, and clearly define the size error standards of key feature points to guide the rapid decision-making of process inspection. For the inspection method, the first and last materials of the coil material are normally inspected offline, with comprehensive inspection and record-making. After the mass production is stable, the first sheet material of each pallet is inspected online quickly to reduce the scrapping of sheet materials caused by manual lifting of materials in offline inspection, damage from oilstone grinding, and oil film wiping.
Optimization control of equipment and tooling factors
(1) Downgrading inversion loss. During the clamping and flipping process of steel pallets and alloy material stacks, quality damage occurs due to rigid contact. To reduce the degree of damage, wooden pallets can be used, or acrylic sheets can be laid at the contact position between the steel pallets and the flipped material stacks to isolate the rigid contact between the material stacks and the copper pallets. When not in use, the acrylic sheets should be stored in a clean environment. The sheet materials inspected during the process are not directly discarded and scrapped. They can be reused for the upper and lower sheets of sheet materials after sheet material flipping, reducing the repetitive loss in the production process.
(2) Strengthen the TPM of equipment and tooling, with prevention as the priority. Based on the PFMEA and CP of the uncoiling line, identify potential risk points and key control items, set and implement TPM at different levels, and take preventive measures in advance to reduce the failure rate.
Optimal control of quality accident losses
Strengthen the control of process details and avoid losses through standardized operations and identifiable standards.
(1) Regarding the cleaning of the material stack on the uncoiling line, before packaging, the side walls, bottom and upper surfaces of the material stack should be wiped horizontally with a dust-removing cloth. Avoid using fibrous mold cleaning paper or cloth to prevent the residue of fibrous substances on the material stack due to back-and-forth wiping, which may affect the cleanliness. A vacuum cleaner can be used to clean the dirt and foreign objects on the bottom and side packaging paper (film). The length of the wrapping paper (film) is moderate. If it is too long, it will be piled up on the first sheet of board material. If it's too short to cover, the tape is likely to stick to the sheet material, affecting the quality of the first material.
(2) Regarding the cleaning of the uncoiling line tray, use a dust-removing cloth to clean the areas in contact with the sheet material. At the same time, use a vacuum cleaner or air pipe to remove any dirt or foreign objects remaining in other parts of the tray.
(3) Regarding the cleaning of the unpacking of the stamping line, during the unpacking process of the material stack, it is strictly prohibited to use tools to cut the packaging film to avoid scratching the sheet material and causing the cut packaging film debris to fall off, which may affect the cleanliness. Tear off the top transparent tape without damaging the plastic film, and check the surface of the material stack and the top for any foreign objects and clean them up.
(4) Regarding the usage standards of the first and last parts of the stamping Yudi, based on the common appearance problems of the first sheet metal (indentation/dent/scratch/deformation/dirt and oxidation/transportation damage/uneven oil film), and in combination with the usage requirements of different types of parts, the handling standards for clean use, repair, return, and scrapping have been defined respectively. If the first dent defect is located in the scrap area of the outer plate or on a non-visible surface, and the dent depth is less than 1/3 of the material thickness, it can be released for production. If the number of dents is more than 3, it will be returned. If there is a defect of edge wave deformation and the deformation of the edge (20mm width) is less than 5mm, it will be released for use; if it exceeds 5mm, it will be returned.
(5) In terms of controlling packaging quantity errors, the counter should be calibrated regularly. For sheet materials that are prone to quantitative errors, a method of offline manual secondary review is adopted. For the left and right side-flipping and dragging of sheet materials or the merging of sheet materials, process records should be well kept and information transmission between the upper and lower processes should be ensured. The management of the material stack flow cards should be strengthened.
