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Mold Core and Cavity Machining

Mold core and cavity machining in H13, S7, D2 and A2, held to ±0.005 mm with polished surfaces to Ra 0.2 µm. No MOQ, prototypes in 3–5 days, every drawing engineer-reviewed.

  • ±0.005 mm

    Milled & Ground

  • Ra 0.2 µm

    Polished Finish

  • 3–5 days

    Prototype Lead

CNC milling cutter machining a hardened mold cavity block
ISO Certified ISO 9001, ISO 13485, AS9100D
Finished mold core and cavity inserts on dark worktable

Mold Components Manufacturing Since 2002

Mold core and cavity machining is DEK’s oldest trade: founded in 2002, we supplied core pins, ejector pins and guide bushes to mold makers. Today we machine cores, cavities, inserts, slides, lifters and ejector pins in H13, S7, D2, A2, O1 and 420 stainless.

Mold components are part of our custom CNC machined parts catalogue, machined to your design with wire EDM and grinding. Mold design and injection molding are not covered here.

Types of Mold Components We Machine

Cores, cavities, inserts, pins, electrodes and die details machined from hardened, pre-hardened or annealed tool steel blocks.

  • Hard milled mold cavity block in tool steel on worktable
    Cores and Cavities
    From hardened or pre-hard blocks, hard milled after heat treatment.
    H13 Hard Milling
  • CNC milled and wire-cut mold inserts on dark worktable
    Mold Inserts CNC Machined
    Cavity, core, gate and vent inserts, CNC milled and wire-cut.
    Wire EDM Stainless 420
  • Mold slide and lifter with ground angled face on worktable
    Slides, Lifters and Wedges
    Slides, lifters, wedges and wear plates with ground angled faces.
    Tool Steel S7 Grinding
  • Precision ejector pins and sleeves on dark worktable
    Ejector Pins and Sleeves
    Ejector pins, ejector sleeves, core pins and blade ejectors.
    h6 ground H7 hole
  • Copper sinker EDM electrodes on dark worktable surface
    Sinker EDM Electrodes
    Electrodes in C110 copper, machined in-house for sinker EDM work.
    Copper C110 Sinker EDM
  • Stamping die punch and die button on dark worktable
    Stamping Die Components
    Punches, die buttons, stripper plates and form blocks for stamping.
    Tool Steel D2 Tool Steel S7
  • Pre-hard steel rapid tooling insert on dark worktable
    Rapid Tooling Inserts
    Inserts in aluminum or pre-hard steel for rapid tooling programs.
    Aluminum Pre-hard Steel

Mold Core and Cavity Machining Specs

Tool steels, EDM and grinding routes, measured tolerances and finishes for cores, cavities, inserts and die details.

  • Tool Steels for Mold Inserts CNC Work

    Grade follows the job: hot-work, shock, wear or corrosion resistance.

    • H13 for cores and cavities, 48–52 HRC
    • D2 for high-wear die buttons, 58–62 HRC
    • Stainless 420 for PVC and medical molding
    Tool Steel Grades
    Material Why it is used
    Tool steel H13 Cores, cavities; 48–52 HRC
    Tool steel S7 Punches, slides; 54–56 HRC
    Tool steel D2 Die buttons, edges; 58–62 HRC
    Tool steel A2 Stable gauges and inserts
    Tool steel O1 Low-cost short-run die details
    Stainless 420 PVC and medical mold inserts
    Copper C110 Sinker EDM electrodes
  • How Mold Core and Cavity Machining Works

    Milling, EDM and grinding run under one roof, with finish machining after hardening.

    EDM Services
    Process Used for
    CNC milling Roughing, finishing, hard milling
    Sinker EDM Sharp corners, ribs, deep cavities
    Wire EDM Through-profiles, insert outlines
    Wire EDM Ejector-pin holes in hard steel
    Precision grinding Parting faces, shut-offs, pockets
    Heat treatment Hardening before finish machining
  • Die Machining Services Tolerances

    Measured capability for inserts, blocks and pins, verified on CMM.

    • ±0.005 mm milled, ground and wire-cut
    • Parting faces ground to 0.003 mm parallelism
    • Pin holes H7, pins ground to h6
    Get a Quote
    Specification Typical capability
    Insert and block size Up to 500 × 500 × 300 mm
    Milled and ground tolerance ±0.005 mm
    Wire EDM profile ±0.005 mm; Ra 0.4 µm skim
    Sinker EDM detail Corner R 0.05 mm; Ra 0.4 µm
    Parting-face parallelism 0.003 mm ground
    Ejector-pin hole fit H7 hole; pins ground h6
    Surface finish Ra 0.8 milled; Ra 0.2–0.4 polished
    Hardness H13 48–52; D2/A2 58–62 HRC
  • Finishes for Mold Components

    Finishes are applied only to components DEK machines.

    All Finishes
    Finish Applied to
    Nitriding H13 cores, glass-filled resins
    Polishing Cavity surfaces, drawing grade
    PVD TiN or CrN Wear or release surfaces
    DLC coating Low-friction slides

Design Tips for Mold Components and Dies

Drawing callouts that decide cost, route and tool life for cores, cavities, inserts and ejector pins.

  • Hardness and Machining Order

    State hardness and whether finish machining follows heat treatment; it costs more but removes distortion risk.

  • Internal Corner Radii

    Radii under 0.2 mm imply EDM, so say which faces are EDM-acceptable on the drawing.

  • Ejector-Pin Hole Patterns

    Dimension holes as a pattern from one datum with an H7 fit and a counterbore length tolerance.

  • Polish Grade and Direction

    Call out draft, SPI or VDI 3400 grade and direction on every molding surface; "polish" alone is not a spec.

  • Replaceable Inserts

    Design gate and wear-prone core inserts as replaceable pieces to avoid re-machining the whole cavity block.

What to Call Out on Your Drawing

  • STEP Model and Drawing

    Send a STEP model with the drawing; every insert is checked on CMM against the model before shipment.

  • Steel Grade and Hardness

    Give the grade (H13, S7, D2, A2, O1, 420) and target HRC; hardness is verified after heat treatment.

  • Polish Grade

    Name SPI or VDI 3400 per surface: Ra 0.8 µm milled, Ra 0.2–0.4 µm polished, mirror polish on request.

  • Quantity and Lead Time

    No MOQ: a single replacement insert or a set of ejector pins is quoted and ships in 3–5 days plus heat treatment.

Mold Machining Services by Industry

Mold machining services and custom tooling manufacturing for mold builders in automotive and consumer products, plus 420 stainless inserts for medical.

Why DEK for Mold Components Manufacturing

Over 20 years supplying mold makers, with inspection habits built for tool components.

  • 20+ Years With Mold Makers

    Founded in 2002 supplying core pins, ejector pins and guide bushes to mold makers; ISO 9001 passed in 2005.

  • Misumi Vendor Since 2012

    A Misumi supply-chain vendor since 2012, so tool component inspection routines are long established.

  • CMM and Hardness Checks

    Every insert is checked on CMM against the model, pins are gauged and hardness is verified after heat treatment.

  • One Roof, One Route

    Milling, wire and sinker EDM, grinding and polishing run in-house, holding ±0.005 mm on finished features.

Engineer Review on Every Drawing

Every drawing is reviewed by an engineer before quoting. DEK is ISO 9001:2015, ISO 13485 and AS9100D certified by TÜV, and machines mold and die components to your design.

Certified Quality for Tooling

ISO 9001:2015, ISO 13485 and AS9100D certified by TÜV.

  • AS9100D and ISO 9001 certification logo
    AS9100D

    Aerospace Quality Management System

  • ISO 9001 certification logo
    ISO 9001:2015

    Quality Management Standard

  • ISO 13485 certification logo
    ISO 13485

    Medical Devices Quality Management

Mold Components FAQ

Hardened steel, single inserts and scope: answers for mold builders.

Do you machine mold cores and cavities from hardened steel?
Yes. Blocks in H13, D2 or A2 are hard milled at 50+ HRC, with sharp corners and deep ribs burned by sinker EDM and profiles cut by wire EDM, so the finished size is the size after hardening.
Can you supply single mold inserts or replacement ejector pins?
Yes. There is no MOQ. A single replacement insert, a set of ejector pins or a worn gate insert is quoted from your drawing and typically ships in 3–5 days plus heat treatment time.
Do you offer mold design or injection molding?
No. This page covers mold components manufacturing and die machining services from your designs; DEK does not offer mold design, and injection molding is not the subject of this page.

Get a Quote for Tool and Die Services

Send a STEP model and drawing with steel grade, hardness, polish grade and quantity. Every drawing is reviewed by an engineer.

  • Simple inserts and pins quoted within 6 hours
  • Core and cavity sets quoted within 3 days
  • No MOQ, single inserts welcome
  • Prototypes ship in 3–5 days
  • ±0.005 mm milled, ground, wire-cut
Request an Aerospace Quote