1 Scope
This document specifies the precision cold-forming process specification for sheet metal, including general requirements, bending length, bending accuracy, bending rebound control, die design and process.
This document applies to sheet metal in the press precision cold-forming process preparation.
2 normative reference documents
The content of the following documents through the normative references in the text and constitute the essential provisions of this document. Among them, note the date of the reference document, only the date of the corresponding version applies to this document; do not note the date of the reference document, its latest version (including all the revision of the list) applies to this document.
GB/T 4863 Basic terms for mechanical manufacturing processes
GB/T 8541 Terminology of forging and pressing
GB/T 13914-2013 Dimensional tolerances for stamped parts
GB/T 13915-2013 Angular tolerances for stamped parts
GB/T 13916 Unannotated tolerances for shape and position of stamped parts
GB/T15055 Dimensional limit deviations for unannotated tolerances of stamped parts
JB/T 5109-2001 Specification for sheet metal press bending process without juice
3 Terms and definitions
The terms and definitions defined in GB/T 4863 and GB/T 8541 apply to this document.
4 General provisions
4.1 General requirements
4.1.1 You commonly used materials should comply with the minimum bending radius JB / T 5109-2001 provisions. When the bending line and the rolling direction into a certain angle, should be taken perpendicular and parallel to the rolling direction of the middle value of the two.
4.1.2 bending parts of the structure of the process should be consistent with the provisions of JB/T 5109-2001.
4.1.3 precision cold forming equipment selection should be consistent with the provisions of JB/T 5109-2001.
4.2 Bending parts unfolded length
4.2.1 neutral layer of the radius of the arc calculation method
4.2.2 neutral layer arc length simplified calculation
4.2.2.1 bend 90 ° part of the neutral layer arc length of the arc should be calculated according to JB/T 5109-2001 Appendix B in Table Bl.
4.2.2.2 U-shaped parts of the bending rounded part of the neutral layer arc length in accordance with Appendix A, Table A.1 calculation.
4.2.3 Bending part of the unfolded length calculation
4.2.3.1 Bending length shall be calculated in accordance with the calculation procedure specified in JB/T 5109-2001.
4.2.3.2 specific conditions, bending length can be calculated according to JB/T 5109-2001 Appendix A table Al and table A2 of the empirical formula.
4.3 Bending accuracy
4.3.1 bend size tolerance should be in accordance with GB/T 13914-2013 FT6 implementation.
4.3.2 bending angle tolerance should be in accordance with GB/T 13915-2013 in the table A.2 corresponding to the corresponding thickness of the highest tolerance level.
4.3.3 Bending parts not noted shape tolerance should be implemented in accordance with GB/T13916.
4.3.4 bending parts not noted tolerance size limit deviation should be implemented in accordance with GB/T15055.
4.4 Bending rebound control
4.4.1 Rebound control method
4.5 Mould design
4.5.1 Mould structure design
It is desirable to use the three-way compressive stress state of the mold structure design.
4.5.2 Bending mould working part size
Bending die working part dimensions mainly include the radius of the convex die corner, convex die corner, concave die depth and concave die corner radius; for U-shaped parts of the bending, also includes the gap between the convex and concave die and width dimensions.
5 Processes
5.1 General process flow
General process flow should include: preparation, material, bending and testing.
5.2 Preparation
5.2.1 The size of the blank should be determined according to the unfolded length of the bent part.
5.2.2 should be based on the batch, size, etc. Select the type of mold, batch size and small size of the bending parts should be used for progressive die or composite die.
5.2.3 In addition to bending parts in the work part size and shape should be implemented in accordance with this document, other parts of the structure and components, according to the corresponding die specification design.
5.2.4 The working surface of the die should be cleaned and wiped, and the surface should be inspected to ensure that there are no scratches, abrasions or adhesions.
5.2.5 A suitable press should be selected according to the required bending force and the size of the die.
5.2.6 The accuracy and clearance of the die after installation should be checked to ensure that it meets the requirements.
5.2.7 Necessary commissioning, inspection and lubrication should be carried out on the entire bending unit.
5.3 Discharge
5.3.1 Layout design, should avoid making the bending line parallel to the rolling direction.
5.3.2 Bending part of the blank can be used punching, shearing or cutting, cutting and other methods of preparation.
5.3.3 bending before the blank should be cleaned burrs, sharp edges and other excess.
5.3.4 Bending the surface of the blank should be bright and clean, no obvious bumps and Liu Zhen.
5.4 Bending
5.4.1 Bending blanks should be positioned accurately.
5.4.2 multi-process bending, should first bend the two ends, after bending the middle part; each process should be reliably positioned, and avoid affecting the shape of the previous sequence has been formed.
5.4.3 bending, the amount of rebound should be large, the need to debug the repair process arranged in the follow-up process.
5.4.4 burr side should be in the corner of the bend.
5.4.5 bending should be taken when the lubrication measures.
5.5 Inspection
5.5.1 should be the first piece of bending parts for testing, the first piece of testing after passing, before processing.
5.5.2 The surface of the bending parts should be free of abrasions, scratches and cracks.
5.5.3 should be based on the drawings of the bending size and angle accuracy testing.
5.5.4 batch bending, bending parts should be quantitative sampling inspection.
Appendix A (normative) U-shaped part of the bending rounded neutral layer arc length calculation table
Bibliography
1 Scope
2 normative reference documents
3 Terms and definitions
4 General provisions
5 Processes
Appendix A (normative) U-shaped part of the bending rounded neutral layer arc length calculation table
Bibliography
