Celah Pisau Shear: Mekanisme, Celah Per Sisi vs Celah Total, SOP Pengaturan, dan Pemicu Kontrol Kualitas

Jawapan Cepat: Celah pisau shear diatur pada 5–10% dari ketebalan material, diukur pada titik pemotongan. Untuk baja lunak (mild steel) 6 mm, itu berarti celah 0,30–0,60 mm — namun persentase tersebut adalah kisaran awal, bukan jawaban akhir. Konfirmasikan nilai kerja dengan potongan uji pada material aktual Anda, verifikasi celah pada tiga titik di sepanjang pisau menggunakan feeler gauge (measuring gauge), dan perlakukan ketinggian burr apa pun di atas 5% dari ketebalan sebagai pemicu untuk memeriksa ulang celah tersebut.

Catatan Teknik: Celah pisau shear adalah celah tegak lurus antara tepi potong atas dan bawah, yang dinyatakan sebagai persentase dari ketebalan material. Celah ini mengatur rasio zona burnished (halus) terhadap zona patah pada tepi potong, tinggi burr, dan beban pisau per langkah potong. Alur kerja pengaturan dan kontrol kualitas Maxtor Metal memperlakukan celah sebagai parameter proses yang spesifik terhadap material — bukan pengaturan mesin yang tetap — dan mendokumentasikannya untuk setiap pekerjaan beserta kondisi pisau dan pembacaan radius tepi.[→ See Maxtor Metal shear blade specifications and material options]

Celah pisau shear adalah jarak horizontal antara tepi pisau atas dan bawah pada titik pemotongan, dan pada mesin shear guillotine biasanya diatur sebagai persentase dari ketebalan material daripada angka tetap. Pengaturan yang salah menimbulkan biaya yang sangat nyata: afval/sampah strip akibat kualitas tepi yang buruk menyumbang 5%–10% dari total biaya kepemilikan — sebuah angka yang terus terakumulasi di setiap siklus penggerindaan ulang.

The 5–10 percent rule is a starting range rather than a specification. Treat the machine manual as the authority, then find the working value by iterating on the actual sheet, blade sharpness and rake angle (Ursviken, 2025). Note the convention split: some suppliers state blade clearance per side, others state the blade-to-blade gap, so confirm which figure the Maxtor Metal shear blade specification uses before you dial anything in. Maxtor Metal works to the per-side reading, which doubles the number at the gap.

Poin-poin Utama

• Celah pisau shear adalah persentase dari ketebalan material, yang diatur pada titik pemotongan.
• Kisaran 5–10% adalah rentang awal; manual mesin menentukan nilai akhirnya.
• Konfirmasikan apakah angka yang dipublikasikan adalah celah pisau per sisi atau total celah antar pisau.
• Kualitas tepi yang buruk menyumbang 5%–10% dari total biaya kepemilikan melalui afval strip.

Catatan tentang sumber: Panduan ini mengacu pada referensi pemotongan shear yang dipublikasikan — Panduan AHSS, dokumentasi proses pemotongan ispatguru, dan panduan pembuat peralatan dari Ursviken dan Sureay — bersama dengan pengalaman lapangan Maxtor Metal sendiri. Jika suatu angka berasal dari sumber independen, angka tersebut dikutip sebagaimana mestinya; jika angka tersebut mencerminkan batas penerimaan internal produsen, hal itu dinyatakan secara jelas agar Anda dapat mempertimbangkannya dengan baik.

Mekanika Tepi Potong

Shear blade clearance decides how a cut fails, and that failure is what produces either a clean edge or a burr. The mechanism is worth understanding because it explains why the recommended band moves with material and thickness rather than staying fixed.

In short: clearance controls the split between smooth burnish and rough fracture on the cut edge — understanding this mechanism is what turns the 5–10% band from a guess into a tuning range.

Burnish and fracture zones

A sheared edge is not one surface. It is four zones stacked through the material thickness: rollover, where the blade first contacts and plastically deforms the sheet into a rounded, bent region; the burnish or shear zone, a smooth band formed while the blade compresses and rubs the material; the fracture or rupture zone, a rougher angled region where the crack propagates; and the burr, thin elongated metal pushed out at the exit edge (ispatguru, 2019; Pedoman AHSS, 2021).

Rollover and burr formation

Clearance sets the split between the smooth and rough portions of that edge. The burnish zone ends where crack initiation begins, so penetration depth equals rollover height plus burnishing zone height. The rough fracture zone then grows with ductility, thickness and clearance, which means a larger clearance shrinks the burnish share, enlarges the fracture share, and pushes more material into the burr (ispatguru, 2019).

Force, rake, and clearance interplay

The general shearing range runs from 2% to 10% of material thickness, and the correct point inside that range depends on the workpiece. Harder materials and greater thickness need larger clearance. Set it too wide and the edge comes out rounded and distorted with a burr and a higher shearing load; set it too tight and the blade leaves a double cut, sometimes called secondary shearing. Ductile material produces a taller burr at any given clearance (ispatguru, 2019).

That is the mechanism behind the band. The next section turns it into numbers.

Aturan 5–10%

The 5–10 percent rule says the shear blade clearance should sit between 5% and 10% of the metal thickness you are cutting. That band is the starting point for mild steels, not a universal setting, and the Pedoman AHSS note that published recommendations place mild-steel die clearance at 5% to 10% of metal thickness. The same source flags a convention trap worth settling before you touch the machine: for punched holes, those figures are per-side values. Vendor charts on the open web often frame the identical 5%–10% band as the total blade-to-blade gap instead. Confirm which convention your chart uses before you convert a number into a shim stack, because a 10 mm mild-steel cut reads as 0.5–1.0 mm per side under one reading and 0.5–1.0 mm total under the other.

In short: the 5–10% band is a defensible starting range for mild steel, not a universal answer — the working value must be confirmed by test cut on the actual material, and the convention (per side vs total gap) must be established before any number is set.

Material-based bands

The band widens as the material gets stronger. The AHSS Guidelines put the range at roughly 6% for mild steel, rising to 16% or higher once tensile strength passes 1400 MPa, and note that ISO 16630 hole-expansion testing specifies 12% punch-to-die clearance while optimal clearance for advanced high-strength steel appears to be approximately 15%. Treat those as directional anchors rather than a lookup table: they come from a technical body’s guidance program, and the underlying figure is a historical baseline rather than a recent test series.

For AHSS and UHSS applications where standard D2 blades are reaching their clearance and wear limits, see the panduan ROI pisau shearing sisipan tungsten carbide untuk lini AHSS untuk perbandingan TCO lengkap.

When to deviate

Deviate upward when the material work-hardens or when edge quality matters more than tool life. Deviate downward only when your press capacity is the binding constraint, since tighter clearance raises cutting force. The honest position is that 5%–10% is a starting point you tune from, not an answer you inherit.

Parallelism and thickness effects

Clearance is only as good as its consistency along the blade. A machine set to 8% at the ends but drifting to 11% mid-blade will burr in the middle and shear cleanly at the edges, which is why parallelism is checked separately from the nominal gap. Thicker stock amplifies the same error: the absolute gap grows with thickness, so a fixed mechanical misalignment becomes a larger percentage deviation.

SOP Pengaturan

A repeatable shear blade clearance setup follows one sequence: baseline the gap, verify parallelism, lock, test cut, iterate. The steps below assume the machine is locked off, the blades are clean and correctly seated, and you have a feeler gauge set, a dial indicator with a magnetic base, and scrap of the material you are about to run. Budget 30 to 45 minutes for a first setup on a machine you do not know well.

In short: measure clearance at three points along the blade before every setup change, verify parallelism within 0.02 mm, lock the adjusters, then iterate from a test cut — the sequence matters because locking adjusters commonly shifts the gap.

Feeler gauge baseline

Set the upper blade to its lowest position and insert the feeler gauge stack at the left end, center, and right end of the blade. Three points is the minimum; add points every 500 mm on blades longer than 2 m. Adjust the gap until the gauge drags with light resistance rather than passing freely or binding. Record all readings before touching anything else, because the spread across those points tells you whether you are correcting clearance or parallelism.

Dial indicator calibration

Mount the dial indicator on the lower blade and sweep the upper blade through its stroke, recording readings at several positions along the length. Blades should sit within 0,02 mm of each other, and the gap needs immediate recalibration once it exceeds that. Note what kind of number this is: there is no single ISO standard that sets a shear-blade parallelism limit, so 0.02 mm is Maxtor Metal’s internal acceptance target, not an industry-mandated figure. The relevant general framework is dimensional and geometric tolerancing — ISO 286 defines the IT tolerance grades used for precision blade geometry (IT6 for cutting-edge position, parallelism to the holder reference face, and flatness; IT7 for length, width, and mounting-hole position), and ISO 2768 supplies general tolerances where a drawing carries no individual callout. Treat the 0.02 mm as a tighter-than-general shop specification built on that framework (ISO 286-1:2010; ISO 2768). The reason such a tight target is worth holding is mechanical: on a 3,000–4,000 mm blade, a 0.1–0.15 mm deviation across the length is enough to produce visible taper on the cut edge (consistent with precision blade geometry standards under ISO 286 / ISO 2768). Lock the adjusters and re-check the gap at the same three points; locking commonly shifts it.

Test cut and iteration

Run a slow test cut on scrap and read the edge. Burrs or tearing mean the gap is too large; rubbing or excessive tightness means it is too small. Change clearance in small increments and re-cut rather than adjusting several variables at once, then log the final gap, the material grade and thickness, and the indicator readings against the job number so the next setup starts from a known point.

Each regrind removes material from the blade thickness. For the shim calculation method that compensates for this dimensional change and restores correct overlap after each cycle, see the regrinding thickness reduction compensation and shim stack guide.

Verify your result: the test cut should shear cleanly with no visible taper along its length, and a repeat indicator sweep should hold the gap within 0.02 mm after the adjusters are locked.

Kasus Lapangan: Mengoreksi burr berlebihan pada S355 6 mm

The clearest way to see why 5–10% is a starting rule and not a fixed answer is to walk through a commissioning-style troubleshooting case. This is a representative field case built on documented industry practice rather than a measured customer study: the machine, material and measurement sequence reflect how this problem typically appears on a hydraulic guillotine shear, and the underlying rules — the 5–10% band, the ~10% structural-steel practice, and multi-point feeler-gauge verification — are all publicly documented.

In short: this case demonstrates that a clearance value can sit inside the published 5–10% range and still produce unacceptable edge quality — the percentage is the starting calculation, and the cut edge is the verification tool.

The situation

The problem appeared after the machine was switched from thinner sheet to 6 mm structural steel. The operator kept the previous clearance setting rather than recalculating the gap from the new material thickness — a common error where clearance is treated as a fixed machine setting instead of a material-dependent process parameter. The first test cuts showed a noticeably larger burr on the underside of the cut edge, a relatively short burnished zone, and a more irregular fracture zone. The operator suspected dull blades and considered replacing them.

Attempt 1 — replace the blades (rejected)

The first response was to suspect blade wear. Inspection, however, showed the cutting edges were still serviceable — no significant chipping or abnormal rounding. Replacing the blades without correcting the clearance would have treated the symptom rather than the process condition, so the next step was to verify the actual gap.

Measurement sequence

The machine was stopped and isolated per the site’s maintenance procedure. Blade seats were cleaned and checked for trapped scale, chips and debris. Sheet thickness was measured at several points with a micrometer rather than trusting the nominal 6 mm designation. Clearance was then measured at the left, center and right portions of the cutting length with calibrated feeler gauges. The machine manufacturer’s definition of clearance was used throughout the adjustment. This multi-point approach follows published shear-machine guidance, which requires clearance verification at several points along the blade rather than assuming the machine’s nominal setting equals the actual gap — Mittler Bros. and other shear manuals specify checking left, center and right with feeler gauges, and the Australian Steel Institute notes that optimum clearance depends on both material properties and thickness.

Attempt 2 — keep the 5% setting (insufficient)

After measurement, the initial gap was approximately 0.30 mm — about 5% of the measured 6 mm thickness:

6.0 mm × 5% = 0.30 mm

That value was technically inside the general 5–10% starting range, yet edge quality remained unsatisfactory. This is the key point: a value can sit inside the published percentage range and still not be the optimum setting for a particular machine-and-material combination. Clearance is also affected by blade condition, blade geometry, machine rigidity, alignment, and the mechanical properties of the workpiece. Betenbender’s shear guidance makes the same observation for steel work — roughly 10% of thickness usually gives a good cut edge, and clearance may be increased for harder or thicker material, but not beyond about 15%.

Attempt 3 — increase clearance (resolved)

Clearance was increased progressively toward approximately 0.50–0.55 mm, corresponding to roughly 8–9% of the 6 mm material thickness, then a fresh test cut was made under the same material and machine conditions. Edge quality improved visibly. The important caveat: this is not a claim that 0.50 mm is universally correct for S355 — it is simply the working setting found in this troubleshooting example. Published material studies make the same point about clearance being material-specific: voestalpine’s ALFORM technical data compares 4%, 10% and 16% clearance on 3 mm ALFORM 700 M and shows the cut-section geometry changes markedly with the ratio, with excessive clearance increasing burr and edge denting while reducing the shearing-zone share.

Effect, recorded honestly

Rather than inventing precise burr-height numbers, a credible record notes the observable change:

If a team wants to make this rigorous, the fields worth adding are burr height (mm), rollover height (mm), burnished-zone and fracture-zone percentages, cut-angle deviation, machine hydraulic pressure, number of strokes, and blade edge radius.

The takeaway: the 5–10% rule provided the starting window; the test cut identified the working point. The percentage is the starting calculation — the cut edge is the verification tool.

This chain is worth internalising: 5–10% rule → 6 mm S355 gives a 0.30–0.60 mm starting window → measurement shows 0.30 mm gives poor edge quality → step up to ~0.50–0.55 mm → test cut confirms the improvement → do not market 0.50 mm as a “standard value” → every material, thickness and machine combination must be verified by test cut. The AHSS Guidelines reinforce why: clearance is not an isolated variable — a smaller clearance raises cutting force and the demands on tool and machine alignment, while a larger clearance increases rollover and related effects.

Kontrol Kualitas (QC) dan Perawatan

In short: set a numeric burr height limit before the job starts, log clearance and material lot per job, and treat rising burr height or an edge radius above 0.2 mm as mandatory regrind triggers — not subjective judgements.

Burr height limits and triggers

Burr height is the fastest field check on a shear, and it is the one most often left unmeasured. Set a numeric limit before the job starts, then treat any exceedance as a trigger rather than a nuisance.

A practical default is 5% of material thickness. On 3 mm mild steel that is 0.15 mm, measurable with a deburring gauge or a bench micrometer across the burr crest. Project drawings and customer acceptance criteria override the default whenever they are tighter.

Two triggers should stop the line:

• Burr height above tolerance on two consecutive cuts after a clearance check.
• Edge radius at or above 0.2 mm, measured on the blade bevel with a radius gauge or a 20× magnifier.

The second trigger matters because edge rounding, not visible chipping, is what silently widens the effective clearance. A blade that looks serviceable can already be cutting 0.05 mm wider per side than the setup sheet says. As with the parallelism target, the 0.2 mm is a Maxtor Metal internal limit rather than an ISO-mandated value; published edge-radius ranges for industrial blades vary widely by application — some slitting guides cite 0.05–0.30 mm, disc-shear references hold below 0.05 mm, and general deburring practice references edge-break specifications such as ISO 13715. That spread is exactly why you set the limit against your own acceptance criteria rather than assuming one number fits every line.

For a measurement-based rotation trigger and audit-ready log template that standardises this decision across an entire blade inventory, see the Prosedur Operasi Standar (SOP) untuk jadwal rotasi pisau bolak-balik 4 sisi dan kriteria pengasahan ulang..

Kiat Pro: Log clearance, material lot, and burr height per job in one sheet. After a few weeks the log shows whether drift tracks a specific material lot, a specific operator, or the blade itself, which turns regrind scheduling from guesswork into a trend line.

Defect diagnosis and corrective actions

Match the defect to the cause before touching the blade. Most burr and edge complaints trace back to one of four conditions, and each has a different fix.

When chipping appears suddenly or in a consistent location along the blade, the defect pattern itself carries diagnostic information. For a fracture surface analysis workflow that identifies whether the root cause is fatigue (clearance or grinding error) or impact (overload or hardness mismatch), see the shear blade edge chipping root cause guide.

That last decision follows a chipping-depth ladder. Light chipping under 0.2 mm clears with standard stock removal of 0.25–0.35 mm. Moderate chipping between 0.2 mm and 0.5 mm needs deeper removal and a 20× inspection of the bevel. Severe chipping above 0.5 mm means scrap or a major removal that can push the blade past its dimensional safety limit. The floor on any regrind is 0.254–0.381 mm of stock removal, because micro-fractures from running a blade past its sharpening window penetrate 0.25–0.40 mm below the bevel and will surface again if that layer is left in place (Maxtor Metal regrind-or-replace criteria for shear blades, retrieved 2026-08-27).

For a full analysis of how D2 and SKD11 carbide microstructure affects chipping depth and regrind frequency, see the D2 vs SKD11 tool steel shear blade selection guide.

Maxtor Metal’s own QC workflow ties this together: blades are logged against job and material lot, regrind is triggered when edge radius reaches 0.2 mm or burr height exceeds project tolerance, and every returned blade is re-verified for straightness under 0.02 mm/m, parallelism under 0.015 mm, and hardness across the full length before it goes back into rotation. These too are internal acceptance limits, set tighter than the general ISO 2768 / ISO 286 framework rather than drawn from a single published shear-blade standard. The point of the record is not the paperwork. It is knowing which of your four-edge reversible blades still has usable edges and which one is one bad cut away from a scrap decision.

FAQs:

T: Apa aturan 5–10 persen untuk celah pisau shear?

J: Aturan ini menetapkan celah pisau shear sebesar 5% hingga 10% dari ketebalan material. Untuk baja lunak (mild steel) 10 mm, ukurannya adalah 0,5–1,0 mm. Kisaran ini menyempit seiring meningkatnya kekuatan tarik (tensile strength): aluminium lunak berada di dekat batas atas, sedangkan stainless dan HSLA berada di dekat batas bawah. Jadikan ini sebagai titik awal dan konfirmasikan dengan potongan uji pada material aktual yang digunakan.

T: Apakah celah pisau shear dihitung per sisi atau total?

J: Kedua konvensi tersebut muncul dalam tabel yang dipublikasikan, dan mencampuradukhkannya akan melipatgandakan celah Anda. Maxtor Metal menentukan rekomendasi 5–10% sebagai celah pisau per sisi, sehingga pemotongan baja lunak (mild steel) 10 mm berjalan pada 0,5–1,0 mm per sisi, atau total 1–2 mm. Periksa konvensi mana yang digunakan oleh produsen mesin Anda sebelum Anda menyetel apa pun.

T: Berapa celah yang harus saya atur untuk baja lunak (mild steel) 6 mm?

J: Mulailah pada 0,3–0,6 mm dan verifikasi melalui tepi potongan. Tepi yang bersih dan siku dengan pita burnish yang tipis menandakan pengaturan Anda sudah mendekati tepat; rollover yang parah atau burr yang kasar menandakan celah terlalu lebar. Ukurlah burr tersebut daripada sekadar menilai dengan mata telanjang.

T: Bisakah saya menggunakan celah yang sama untuk stainless steel dan baja lunak?

J: Tidak. Stainless, HSLA, dan grade berkekuatan lebih tinggi lainnya memerlukan celah yang lebih rapat, umumnya mengarah ke batas bawah kisaran, karena material tersebut menolak aliran plastik dan lebih cepat patah. Menerapkan celah baja lunak pada stainless steel akan menghasilkan keretakan tepi dan keausan pisau yang lebih cepat.

T: Seberapa sering saya harus menggerinda ulang (regrind) pisau shear?

J: Ketinggian burr adalah pemicu praktisnya: praktik umum menargetkan tinggi burr di bawah 10% dari ketebalan logam, dan peningkatan tinggi burr melacak keausan alat serta pertambahan celah (Panduan AHSS). Untuk baja AHSS, tinggi burr saja merupakan indikator yang lemah, sehingga kualitas tepi potong adalah indikator yang lebih baik. Alur kerja internal Maxtor Metal menggunakan radius tepi 0,2 mm, atau tinggi burr yang melebihi toleransi proyek, mana saja yang tercapai lebih dulu.

T: Bagaimana cara memeriksa sejajar atau tidaknya (parallelism) pisau shear?

J: Gunakan dial indicator pada magnetic base, gerakkan di sepanjang panjang pisau dengan kondisi mesin terkunci dan dimatikan. Maxtor Metal memverifikasi kelurusan di bawah 0,02 mm/m dan kepararelan di bawah 0,015 mm pada tahap produksi — ini adalah batas penerimaan internal yang dibangun di atas kerangka toleransi umum ISO 2768 / ISO 286, sehingga merupakan tolok ukur yang masuk akal untuk mesin yang sedang beroperasi, bukan sekadar angka yang diwajibkan oleh setiap standar. Lakukan pemeriksaan ulang setelah penggerindaan ulang atau penggantian pisau.

T: Mengapa mesin shear saya meninggalkan potongan ganda (double cut)?

J: Potongan ganda biasanya berarti celah terlalu lebar untuk ketebalan material tersebut, sehingga material melengkung ke dalam celah dan patah dua kali alih-alih sekali. Masalah ini juga bisa berasal dari gaya jepit (hold-down force) yang tidak memadai atau pisau yang sudah tumpul. Persempit celah ke arah batas bawah kisaran dan periksa tekanan penjepit sebelum menyalahkan pisaunya.

Kesimpulan

Celah pisau shear adalah keputusan pengaturan, bukan angka tetap, dan aturan 5–10% memberi Anda titik awal yang dapat dipertanggungjawabkan daripada jawaban universal. Rentang ini mengontrol dua hal sekaligus: seberapa banyak zona burnished (halus) dan patah yang dialami tepi, serta seberapa besar rollover dan burr yang ditinggalkan oleh potongan tersebut. Atur dengan benar dan bidang potong tetap bersih; menyimpang dari rentang ini berarti Anda hanya menukar satu cacat dengan cacat lainnya.

Hal yang membedakan proses yang terkontrol dengan proses yang hanya mengandalkan keberuntungan adalah standardisasi. Catatlah celah yang Anda tetapkan untuk setiap pekerjaan, catat grade dan ketebalan material yang dikerjakan, serta periksa kondisi tepi pada interval waktu tetap alih-alih menunggu adanya keluhan tentang burr. Lacak siklus penggerindaan ulang berdasarkan catatan tersebut sehingga Anda dapat melihat keausan tepi sebelum bilah pisau tersebut gagal berfungsi. Anggaplah ini sebagai masalah alur kerja sekaligus masalah pisau: nilai celah yang sama akan memberikan hasil yang berbeda di setiap shift kerja jika tidak ada yang menuliskan dan mencatatnya.

Jika Anda sedang menyiapkan mesin shear baru atau menyeragamkan mesin yang sudah ada, tinjau spesifikasi pisau terhadap campuran material dan siklus kerja (duty cycle) Anda sebelum menetapkan angka tertentu. Ketika material atau aplikasi berada di luar kisaran normal, diskusikan dengan application engineer mengenai di mana proses Anda harus menyimpang dan alasannya.

For the full Maxtor Metal shear blade range — material grades, dimensional tolerances, and regrind service options — see the precision shear blade product page.

Tentang Penulis: Pengalaman Lapangan di Balik Panduan Ini

This guide is written and reviewed by Jerry Chu, Technical Support Specialist in Maxtor Metal’s After-sales Service team. Jerry has 10 years of hands-on experience with industrial cutting blades across paper making, plastic granulation, metal slitting and slitting lines, and wood processing — applications where burr formation, edge quality, and dust generation all show up as real production problems rather than theory. That field background shapes the setup and QC guidance here: the focus on measurable triggers (burr height, edge radius, parallelism) rather than subjective “looks fine” judgements comes directly from troubleshooting these issues on customer lines.

Jerry holds PMP (Project Management Professional) dan CMRP2 certifications, which support the process-discipline approach — logging, standardised setup, and scheduled inspection — that runs through this article.

Maxtor Metal is a manufacturer and supplier of custom, precision-ground industrial blades with over 15 years of experience, serving engineers, technical buyers, and equipment manufacturers worldwide. The company operates a quality management system certified to ISO 9001, and manufactures blades to customer drawings, sketches, or photos with material selection aimed at extending blade life. The internal tolerance and regrind figures quoted in this article come from that QC workflow.