Punching parts are sheet-metal components produced by pressing a hardened punch through a metal blank to shear, pierce, blank, or form precise features — including holes, slots, louvres, knockouts, and embossments. The process is governed by the fundamental shear-stress relationship described in the SME Tool and Manufacturing Engineers Handbook (4th ed., Vol. 2, §14): punch force F = k · τ · t · L, where τ is the ultimate shear strength of the material, t is sheet thickness, L is the shear perimeter, and k is a process correction factor (typically 1.1–1.3 for CNC turret punching).
At Zhejiang Jiafeng, punching parts are produced on both CNC turret punch presses (NCT) with a working envelope of 1,500 × 3,000 mm and mechanical punch presses ranging from 45 T to 260 T. These capabilities integrate directly with our sheet metal manufacturing workflow, our precision machining department, and downstream mechatronics integration assembly, giving customers a true one-stop supply chain.
According to Kalpakjian & Schmid, Manufacturing Engineering and Technology (7th ed., Chapter 16), punching (also called piercing) is a shearing operation in which a punch forces material through a die to produce a hole; the removed slug is the scrap while the surrounding sheet is the workpiece. When the removed piece is the desired part, the operation is termed blanking. Both are sub-categories of the broader stamping family, which also encompasses bending, drawing, and coining.
In industrial practice, a single punching part typically combines multiple features produced in one turret-press program: round holes, oblong slots, D-shaped cut-outs, louvres for ventilation, extruded holes for thread tapping, and formed lances for spring clips — all held to the dimensional tolerances specified in ISO 2768-m (±0.15 mm on hole diameter; ±0.20 mm on hole position from edge) for standard production, with tighter grades achievable through precision tooling and CMM verification.
Punching parts differ from laser-cut parts primarily in cycle time and cost-per-feature at high volumes. A CNC turret press can execute 300–1,200 hits per minute (depending on tool type and material), making it significantly faster than laser cutting for sheets with many repetitive features. For complex contour cutting, laser cutting complements punching — a hybrid strategy Jiafeng employs across its sheet metal manufacturing line.
Jiafeng operates both CNC turret punching and conventional mechanical punching. The table below maps each process to its technical characteristics, referencing commonly accepted industry parameters (source: Fundamentals of Modern Manufacturing, Groover, 5th ed., §20.2–20.4).
| Process | Equipment at Jiafeng | Sheet Size / Tonnage | Typical Thickness | Hole Diameter Tolerance | Best For |
|---|---|---|---|---|---|
| CNC Turret Punching (NCT) | CNC Punch Presses | 1,500 × 3,000 mm | 0.5 – 6 mm | ±0.10 mm (ISO 2768-m) | Repetitive holes, louvres, knockouts, formed features in medium–high volume |
| Mechanical Punch Press | Mechanical Presses | 45 T – 260 T | 0.3 – 10 mm | ±0.15 mm (ISO 2768-m) | High-speed blanking, progressive-die parts, large-batch structural brackets |
| Blanking | Mechanical Presses | 45 T – 260 T | 0.3 – 6 mm | ±0.10 – 0.20 mm | Flat blanks for subsequent forming, clips, terminal plates |
| Lance & Form | CNC Turret Press | 1,500 × 3,000 mm | 0.5 – 3 mm | ±0.20 mm | Spring retainers, grounding tabs, snap features |
| Extrusion (Extruded Hole) | CNC Turret Press | 1,500 × 3,000 mm | 0.8 – 3 mm | ±0.10 mm | Threaded bosses (M2.5–M10), PCB stand-offs, self-threading collars |
| Louvre / Ventilation Slots | CNC Turret Press | 1,500 × 3,000 mm | 0.5 – 2.5 mm | ±0.20 mm | Enclosure ventilation, heat dissipation panels, speaker grilles |
Tolerances conform to ISO 2768-m unless otherwise specified. Tighter grades available on request. All punching operations are supported by our full sheet metal manufacturing process chain.
Punchability is governed primarily by the material's ultimate tensile strength (UTS), ductility (%EL), and thickness. The punch-to-die clearance — typically expressed as a percentage of sheet thickness — must be carefully matched to material type to achieve a clean shear zone and minimise burr height. Published guidelines from DIN 9870 and the Machinery's Handbook (32nd ed.) recommend clearances of 5–10% per side for mild steel, 6–12% for stainless steel, and 4–8% for aluminium.
| Material | Common Grades | UTS Range | Max Punchable Thickness | Recommended Die Clearance (per side) | Typical Post-Punch Finish |
|---|---|---|---|---|---|
| Cold-Rolled Steel (SPCC / DC01) | SPCC, DC01, ASTM 1008 | 270 – 370 MPa | 6 mm (NCT); 10 mm (press) | 5 – 8% | Powder coating, zinc plating |
| Galvanised Steel (GI / EG / SECC) | SGCC, DX51D, SECC | 270 – 370 MPa | 3 mm | 5 – 8% | Bare zinc, additional powder coat |
| Stainless Steel | 304, 316, 430 | 485 – 720 MPa | 4 mm (NCT); 6 mm (press) | 6 – 12% | Brushed, passivated, natural |
| Aluminium Alloy | 5052-H32, 6061-T6, 3003 | 190 – 310 MPa | 5 mm (NCT); 8 mm (press) | 4 – 8% | Anodising, powder coat, clear coat |
| Copper & Brass | C11000, C26000, H62 | 220 – 380 MPa | 3 mm | 5 – 8% | Tin plating, passivation, bare |
| Spring Steel | 65Mn, SK5 | 800 – 1,100 MPa | 2 mm (press) | 8 – 12% | Phosphating, heat treatment |
UTS values are indicative ranges per material standard (EN 10130, ASTM A1008, JIS G3141). Actual values vary with thickness and temper. All materials are verified by our in-house ROHS and X-ray element analysers before production begins.
Jiafeng manufactures punching parts to the tolerance grades defined in ISO 2768 (general tolerances for linear and angular dimensions) and ISO 286-1 (limits and fits for hole and shaft features). CMM verification with accuracy E = (1.9 + 3L/1,000) µm and CCD optical inspection at ±50 µm provide full dimensional traceability per ISO 10360-2.
| Feature | Standard Tolerance | Precision Tolerance | Reference Standard | Verification Method |
|---|---|---|---|---|
| Punched Hole Diameter | ±0.15 mm | ±0.05 mm | ISO 2768-m | CCD optical inspector (±50 µm) |
| Hole Position (from datum edge) | ±0.20 mm | ±0.10 mm | ISO 2768-m | CMM or CCD vision system |
| Slot Width | ±0.15 mm | ±0.08 mm | ISO 2768-m | CCD optical inspector |
| Burr Height (max) | ≤ 0.10 mm (t ≤ 2 mm) ≤ 0.15 mm (t > 2 mm) |
≤ 0.05 mm | ISO 9013 (adapted) | Profilometer or CMM |
| Blank / Part Flatness | 0.5 mm / 300 mm | 0.2 mm / 300 mm | ISO 1101 | CMM surface scan |
| Extruded Hole Thread (tapped) | 6H class (internal) | 5H class (internal) | ISO 965-1 | Thread gauge (Go/No-Go) |
| Hole True Position (GD&T) | ⌀ 0.30 mm | ⌀ 0.15 mm | ASME Y14.5 / ISO 1101 | CMM with best-fit datum |
All inspections conducted on our High-Precision CMM [E = (1.9 + 3L/1,000) µm, ISO 10360-2] and Precision Sheet Metal Vision Inspection System (±50 µm, planar). First-article inspection reports provided on request.
Punching parts are specified wherever high volumes of precise apertures, formed features, or blanked profiles are required. The following table summarises the industries Jiafeng serves and the typical punching-part types produced for each, consistent with our broader sheet metal manufacturing and mechatronics integration capabilities.
| Industry | Typical Punching Parts | Critical Requirements | Preferred Material | Typical Surface Finish |
|---|---|---|---|---|
| Power & Energy | Busbar brackets, mounting plates, cable-entry knockouts, switchgear panels | IP-rated sealing, arc-flash resistance, UL/CE conformance | SPCC, SECC, Copper | Zinc plating + powder coat |
| Telecom & Data Centre | 19-inch rack blanking panels, cable management plates, vented top covers, EMC gasket frames | EMI/RFI shielding, precise 44.45 mm (1U) pitch hole patterns | SECC, SPCC | Zinc plating (EG) |
| Medical & Healthcare | Instrument trays, perforated shelves, diagnostic housing panels, ventilation screens | Low burr (≤0.05 mm), cleanable surfaces, biocompatibility, ISO 13485 | 304 / 316 SS | Passivation, electropolish |
| Semiconductor Equipment | Cleanroom bracket arrays, vacuum-chamber port covers, wafer-carrier guide slots | Particle control, ultra-flat (≤0.2 mm/300 mm), positional accuracy ±0.10 mm | 304 SS, Al 5052/6061 | Passivation / hard anodise |
| Industrial Automation | PLC cabinet mounting plates, servo-drive mounting brackets, guard panels, cable trays | Structural rigidity, fast delivery, modular bolt patterns | SPCC, GI | Powder coat (RAL custom) |
| Retail & Vending | Product-lane dividers, inner shelf frames, door lock plates, coin-return plates | Cosmetic finish, tight slot widths for product lanes, anti-corrosion | SPCC, Al 5052 | Powder coat, silk-screen |
| Financial Equipment | ATM front-panel apertures, cash-recycler guide rails, tamper-evident lock plates | Tight dimensional control, tamper evidence, aesthetic finish | SPCC, SECC | Powder coat, silk-screen |
Both punching and laser cutting are core technologies in Jiafeng's sheet metal manufacturing facility. Selecting the correct process — or combining them — is a critical design-for-manufacture (DFM) decision. The comparison below is based on published productivity benchmarks (Laser Institute of America, Handbook of Laser Materials Processing, 2001, §4.2; Trumpf GmbH, Sheet Metal Technology Guide, 2022 ed.).
| Criterion | CNC Punching (NCT) | Fiber Laser Cutting (3–12 kW) | Best Choice |
|---|---|---|---|
| Repetitive hole arrays | Up to 1,200 hits/min; very fast | Slower per hole; higher energy | Punching |
| Complex external contours | Limited; requires special tooling | Any 2D profile, kerf ≈ 0.2 mm | Laser Cutting |
| Formed features (louvres, extrusions) | Integrated in one setup | Not possible | Punching |
| Thick plate (> 6 mm) | Requires high-tonnage press | Up to 25 mm (steel) with 12 kW | Laser Cutting |
| Burr height | ≤ 0.10 mm (with sharp tooling) | Virtually burr-free | Laser Cutting |
| Edge squareness / rollover | Rollover zone ≈ 10–20% of t | Perpendicular edge, ≤ 0.1 mm taper | Laser Cutting |
| Cost per part at high volume (> 5,000 pcs) | Lower (no assist-gas cost, fast cycle) | Higher gas + power cost per part | Punching |
| Noise & vibration | Higher (impact noise) | Low | Laser Cutting |
For optimal results, Jiafeng's DFM team recommends a hybrid approach: CNC punching for repeated interior features + fiber laser cutting for complex outer contours. Consult our precision machining engineers at the quotation stage to determine the most cost-effective strategy for your part.
Every punching part order is executed through a documented, ISO-aligned production chain. Because Jiafeng performs all steps in-house — including downstream electromechanical integration — there are no sub-contractor handoff delays or traceability gaps.
The following design-for-manufacture rules are based on industry-accepted guidelines from Benson, T., The Turret Punch Press — A Production Tool (SME, 1993) and Jiafeng's in-house process limits. Adhering to these rules avoids distortion, tool breakage, and excessive burr, while enabling prototype-to-production cost reductions of 15–30% (per SME DFM case studies).
| Design Feature | Minimum Value | Recommended Value | Reason |
|---|---|---|---|
| Hole diameter (round) | = sheet thickness (t) | ≥ 1.2 × t | Prevents punch breakage from tensile stress |
| Slot width (oblong hole) | = t | ≥ 1.5 × t | Avoid tool deflection and slot distortion |
| Hole-to-edge distance | = t | ≥ 1.5 × t | Prevents edge bulging and burr on the cut edge |
| Hole-to-hole spacing (centre-to-centre) | = 2 × t | ≥ 2.5 × t | Prevents webbing collapse between adjacent holes |
| Hole-to-bend distance | = 1.5 × t + bend radius | ≥ 2 × t + bend radius | Prevents hole distortion during subsequent bending |
| Extruded hole collar height | 0.8 × t | 1.0 – 1.5 × t | Provides sufficient thread engagement (min 2 turns) |
| Corner radius (square / rectangular punch) | 0.5 mm | ≥ 1.0 mm | Extends tool life; reduces stress concentration |
| Notch depth-to-width ratio | ≤ 5:1 | ≤ 3:1 | Prevents material tear at notch root |
Values assume standard tool steel punches. For high-strength materials (UTS > 600 MPa), all minimum values should be increased by 20–30%. Jiafeng's engineering team provides free DFM review at the quotation stage.
"Punching parts" refers specifically to components produced by a piercing or blanking operation — the punch shears through the sheet to create a hole or blank. "Stamped parts" is a broader term encompassing punching, bending, drawing, coining, and embossing. All punching parts are stamped parts, but not all stamped parts are punching parts. At Jiafeng, our mechanical presses (45 T–260 T) handle the full stamping spectrum, while our NCT machines specialise in precision CNC punching with complex multi-tool programs.
The minimum punch diameter equals the sheet thickness (1×t) for standard tooling. For a 1.5 mm cold-rolled steel sheet, the minimum round hole diameter is therefore 1.5 mm. Our precision tool library supports round punches from Ø1.0 mm. For holes smaller than the sheet thickness, we recommend switching to laser cutting (available on our 3–12 kW fiber lasers) or drilling on our CNC machining centres.
Yes. Jiafeng's punching parts are regularly fed directly into our electromechanical integration assembly lines. Typical integration-ready punching parts include mounting plates with extruded-hole threads (M3–M8), cable-management trays, PCB support brackets, and DIN-rail mounting plates for PLC cabinets. Surface treatment is completed before assembly to ensure corrosion protection in the final system.
Burr height is controlled through three mechanisms: (1) maintaining correct punch-to-die clearance (5–10% per side for mild steel, per DIN 9870); (2) regular tool sharpening — a dull punch increases burr height exponentially as penetration depth at fracture increases; and (3) in-line deburring using our flat brushing machine (W1,000 mm capacity) for cosmetically sensitive parts. Burr height is verified using profilometer measurement on first-articles; our standard limit is ≤ 0.10 mm for sheet thickness ≤ 2 mm.
Standard lead time is 7–15 business days from drawing approval to shipment for most punching-part orders. Prototype quantities (1–50 pcs) on CNC turret presses require no hard tooling, reducing sampling lead time to 3–5 days. High-volume mechanical-press orders requiring dedicated progressive dies have a tooling lead time of 3–5 weeks, after which production parts ship within 5–10 days per batch. All production, surface treatment, and quality inspection is performed in-house at our Zhejiang sheet metal manufacturing facility to avoid third-party scheduling delays.
Punching parts are the starting point for many Jiafeng assemblies. Continue your journey through our vertically integrated production ecosystem:
