Prototype Mold 7 Day Lead Time

• 1
  What a prototype mold 7 day lead time really measures
• 2
  Why 5-axis machining compresses the schedule
• 3
  Steel choice decides whether the window holds
• 4
  Where the seven days actually go
• 5
  What genuinely cannot be rushed
• 6
  Which molds fit a 7-day build

A prototype mold 7 day lead time is not one fast operation. It is a chain of short operations that overlap, and the clock starts when the 3D model and the steel grade are fixed. Seven days covers programming, roughing, semi-finishing, finishing, electrode work if needed, spotting, and a sample shot. Any single step that slips a day pushes the whole build.

Most shops lose their time in queues, not in cutting. A core block waiting two days for an outside heat-treat furnace is two days gone. A cavity sitting in a polishing room behind production work is another day. Speed comes from removing handoffs, not from running the spindle harder than the tool allows.

The number is worth reading as a boundary, not a slogan. A small insert with simple shutoffs and no deep ribs can finish comfortably inside seven days. A 600 mm housing with ten sliders, a hot runner, and a mirror finish will not, and a shop that says otherwise is either quoting a different scope or planning to ship something unfinished.

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  Clock starts at frozen geometryChanges after steel is cut reset the counter.
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  Steel grade drives the schedulePre-hardened grades skip a heat-treat cycle.
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  Polishing is the hidden dayBench work does not scale with machine speed.

On a 3-axis mill, a core with angled shutoffs, deep pockets, and a curved parting line needs three or four setups. Each setup means unclamping, cleaning, re-indicating, and re-entering the datum. On a simultaneous 5-axis center, the table tilts and the tool reaches the same geometry in one or two setups. That is where the days come from.

Tilting the tool also lets us use shorter, stiffer cutters. A long tool hanging out of the holder chatters, and chatter shows up as witness marks that a polisher then has to grind out by hand. Short tools hold tolerance better and leave a finish closer to final. In practice a cavity can come off the machine at Ra 0.8–1.6 μm and need only light spotting.

High-speed machining paths matter just as much. Small stepovers, high spindle speed, and constant chip load keep heat in the chip instead of the workpiece. That protects the hardness of pre-hardened steel such as P20, NAK80, or 718. If the cut overheats the surface, the mold loses hardness exactly where the plastic will flow.

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  One-setup geometryTilted table reaches angled shutoffs without refixturing.
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  Shorter toolsLess chatter means less bench work later.
• 3
  Controlled heatPre-hardened steel keeps its hardness.

Pre-hardened grades are the default for a prototype mold because they arrive at 28–40 HRC and can be cut directly. P20 and 718 are common for general parts, NAK80 for a better polish, and 1.2343-type steel when the resin is abrasive or the run may extend to tens of thousands of shots. None of these need a hardening cycle before cutting.

A through-hardened tool steel changes the plan. The block is machined soft, hardened at 1,000–1,050 °C, tempered, then finished by EDM or high-speed milling and hand-polished. That is a sound route for a long production mold. For a seven-day prototype it usually does not fit, because the furnace cycle plus a second setup eats three or four days.

Aluminum is the other fast option. A 7075 or QC-10 cavity machines quickly and is fine for low-volume trial shots, but it wears at gates and shutoffs. If the prototype mold is expected to run 5,000 shots or more, steel is the cheaper decision in the end.

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  Stay pre-hardened28–40 HRC, no furnace queue.
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  Aluminum for trials onlyWatch gate wear on longer runs.
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  Hardened steel resets the planBudget the extra days, do not compress them.

Day one is DFM and programming. We check draft, wall thickness, gate location, ejector placement, and parting line, then cut the toolpaths. The 3D model is frozen at the end of this day. Files delivered as STEP or Parasolid with a defined shrinkage factor save hours before the spindle even starts.

Days two and three are roughing and semi-finishing on the 5-axis centers. Day four is finishing of cavity, core, and inserts, plus electrode milling if sharp internal corners are needed. Day five covers EDM for those corners, fitting, and spotting the shutoffs with layout blue.

Day six is assembly, water-line pressure test, and the first sample shot on a trial press. Day seven is dimensional inspection of the shot part against the drawing, adjustment if needed, and packing. This sequence assumes the mold is small to medium, the steel is pre-hardened, and no design change lands mid-week.

• 1
  Day 1DFM, toolpath programming, geometry frozen.
• 2
  Days 2–4Rough, semi-finish, finish, electrodes.
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  Days 5–7EDM, spotting, assembly, sample shot, inspection.

Heat treatment is the clearest wall. A vacuum furnace cycle plus tempering takes a fixed number of hours, and skipping temper leaves residual stress that cracks a cavity weeks later. No amount of overtime removes that time. If the mold needs hardened steel, the honest answer is a longer lead time.

Deep EDM work on sharp ribs is the second wall. A 0.5 mm electrode burning a 30 mm deep rib runs for many hours, and the burn is unattended but not faster for it. Shops that promise to compress this usually mean they will ship the mold with an unfinished corner and let you discover it at the press.

Texturing and engraving sit at the edge. Laser marking with a minimum character height of 1.5 mm is quick and can be done in-house. Acid etching for a leather grain needs an outside vendor and scheduling, which pushes past the window in most cases.

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  Heat treatFixed furnace hours, cannot be compressed.
• 2
  Deep EDMBurn time is set by rib depth and electrode size.
• 3
  Texture etchingOutsourced, so it adds calendar days.