Bend relief removes material where a bent flange meets an adjacent flat area; corner relief addresses the junction of intersecting bends. Review these features before cutting the blank. The required shape and dimensions depend on the material, bend geometry, cutting process and actual tooling. Specify the measurement datum and finished corner requirement instead of copying a single thickness multiplier. A relief cut does not establish machine clearance, load capacity or finished-part acceptance.
Bend relief or corner relief: which problem are you solving?
A partial-width flange leaves material beside the bend that must remain flat. A tray corner joins two bent walls. Both need a deliberate review of how the material can form, but they are different drawing features. A full-width bend with free ends may not need an added relief solely for this reason. Inspect any edge bulging against the part's requirements.
Technical references: SendCutSend; Protolabs.
Match the relief to the finished part
| Drawing situation | Review before release | Finished-part check |
|---|---|---|
| Partial flange beside a flat tab | Identify the bend region and the flat area that must remain undisturbed; dimension both relief ends. | Tab flatness, flange dimensions and condition at the relief ends. |
| Two walls meeting at a tray corner | Review both bends, the sequence, tool access and the intended corner gap together. | Corner gap and fit after both bends, before any specified joining operation. |
| Corner to be welded, sealed or visibly finished | Agree the opening and edge condition with the designer and downstream process owner. | The approved joining/finish requirement; bending alone does not prove sealing or strength. |
Define the dimension reference before using a formula
Relief depth measured from a bend centerline is not the same dimension as extension beyond the bend region. Published fabrication guidance and CAD settings use different references. For example, PTC documents separate bend and corner relief settings and multiple depth modes. Transfer the intended geometry to a dimensioned drawing and inspect the exported flat pattern; a successful CAD unfold is not manufacturing approval.
Technical references: PTC Creo 12.
A drawing record the fabricator can check
| Record | What to specify |
|---|---|
| Material and bend | Grade/temper, thickness, rolling direction where relevant, bend angle, inside radius and the approved bend model. |
| Relief geometry | Shape, width, end radius, depth and its named datum. Identify the bend centerline and bend-region boundaries separately. |
| Cut and formed states | Flat-pattern revision, cutting/deburring requirements, and the required gap or edge condition after all bends. |
| Acceptance and changes | Inspection method, drawing tolerances, representative sample and who approves a change to the relief or tooling. |
Keep the part drawing and flat pattern at the same approved revision. Changing the inside radius or bend model can change the developed geometry and requires another relief review.
Choose a shape with the cutting and forming processes
Rectangular, rounded-end and circular openings are possible design choices, not interchangeable guarantees. Consider the cut process's feature limits, deburring access, the remaining material and the final corner opening. A zero-width CAD rip is not a dimensioned physical slot. Do not enlarge a relief beside a fastener, sealing edge or loaded section without the part designer's approval.
Review the blank, setup and first piece together
- Mark each affected bend and the adjoining flat or bent feature on the drawing. Resolve missing datums and tolerances before cutting.
- Agree the material, bend radius and relief geometry with the fabricator. Check that the selected cutting process can produce the specified shape and edge condition.
- Review the actual punch, die, holders, support and bend sequence. Relief geometry does not replace clearance and load-limit checks for the complete setup.
- Inspect a representative first piece after all relevant bends. Record the corner gap, nearby feature dimensions, edge condition and any distortion against the approved drawing; retain the accepted setup and revision.
Example: a cover with two adjoining flanges
Suppose a cover drawing shows two 90-degree walls meeting beside a mounting hole. This is an illustrative review scenario, not a tested Rucheng part. Agree the finished corner gap first, then dimension the relief and review the hole independently. Check both bend orders with the proposed tools. If the first piece shows a torn edge or distorted hole, hold batch release and review the drawing and setup; do not simply widen the slot and call the part acceptable.
Send both the formed drawing and flat pattern
For a Rucheng press brake inquiry, include the approved part drawing, flat pattern, material, thickness, bend lengths, quantities and inspection requirements. Identify critical corners and nearby holes. Ask for an itemized tooling and machine proposal based on representative parts; any required process trial and supplied configuration must be agreed separately.
Send press brake quote requirementsBend relief questions
Does every press brake bend need a relief cut?
No. A full-width bend with free ends differs from a partial flange or intersecting corner. Decide from the adjacent geometry, forming process and finished-edge requirements.
Can one relief-width or depth formula be used for every material?
No. Confirm the material, bend geometry, cutting limits and dimension reference with the fabricator. A service-specific guideline is not a universal acceptance limit.
Will adding a relief slot fix a hole that distorts during bending?
Not automatically. A slot changes the part and may affect its function. Review hole location, relief geometry, tooling and any secondary operation with the designer, then inspect the first piece.