Scheduled Stop

Annual Demand — also called Estimated Annual Usage (EAU) in North-American injection-molding RFQs — is the total number of identical plastic parts a customer needs in a 12-month window. It is the single most important input for cavitation, mold-class selection, press tonnage and target cycle time in any plastic injection project. In a molding quote, Annual Demand drives every downstream economic decision: number of cavity impressions, SPI mold class (101–105), required clamp tonnage, machine size, runner system (cold vs hot), and the amortization of tooling over the part price. Getting the EAU wrong by 2× usually means a wrong mold — either over-built and never paid back, or under-built and replaced 18 months in. ## Annual Demand vs EAU vs lifetime volume Three figures often get confused in RFQs and must be tracked separately: | Term | Window | Used for | |---|---|---| | Annual Demand (EAU) | 12 months | Cavity count, mold class, press tonnage, machine selection | | Lifetime Volume | Program life (3–7 yr typical for industrial, 1–3 yr consumer) | Mold steel hardness, total mold cycles spec | | Order Quantity / Lot Size | Per release | Inventory, changeover frequency, raw-material POs | A rule of thumb in the industry: if Annual Demand × program years > 1,000,000 cycles, the tool must be SPI Class 101 (production tool, hardened steel, > 1 M cycles). Below 100,000 cycles total, an SPI Class 104 or even Class 105 prototype tool is usually enough. ## How Annual Demand drives cavity count The classic cavitation formula uses Annual Demand directly: `` Required cavities = (Annual Demand × Cycle time s) / (3600 × Annual press hours × OEE) ` Worked example — Annual Demand 1,200,000 parts/year, target cycle 30 s, 5,000 productive press hours per year, OEE 0.80: ` Cavities = (1,200,000 × 30) / (3,600 × 5,000 × 0.80) = 2.5 → round up to 4-cavity mold ` The result is rounded up to the next mold-shop standard (1, 2, 4, 8, 16, 32, 48, 64, 96, 128) for layout symmetry and balanced filling. Higher EAU justifies higher cavitation, but only until tooling amortization stops paying back. ## Typical EAU thresholds in plastics processing | Annual Demand (EAU) | Typical molding decision | |---|---| | < 1,000 parts/yr | Reconsider process: 3D printing, CNC machining or vacuum casting often cheaper than tooling. | | 1,000 – 10,000 | Single-cavity aluminum tool (SPI 105/104), prototype or bridge production. | | 10,000 – 100,000 | Single or 2-cavity P20 steel tool (SPI 103), cold runner. | | 100,000 – 1,000,000 | 2-, 4- or 8-cavity tool, hardened steel (SPI 102), often hot runner. | | > 1,000,000 | High-cavitation 16/32/48/64+ tool, SPI 101 fully hardened, hot runner, automation, ideally dedicated press. | These bands are rough but widely used in quoting; the exact break-even depends on part weight, resin price and cycle time. ## Annual Demand and machine selection Once cavitation is set, the molder works backwards to the press. Required tonnage is calculated from projected part + runner area and material tonnage factor, then a press with at least that clamp force tonnage and the right shot capacity (typically use 30–70 % of shot weight capacity) is selected. A high EAU may justify dedicating one press 24/7 to one mold; a low EAU usually means the tool shares a press with others, which raises changeover cost and lifts the effective cycle time. ## Common pitfalls when stating Annual Demand - Confusing peak-month with annual: customers sometimes state demand as their busiest month × 12. Always ask for the seasonality curve. - Forgetting scrap and color changes: real demand from the press is Customer EAU / (1 − scrap rate − sampling)`. - Ignoring family vs dedicated decisions: when two parts share a design for manufacturing family, splitting Annual Demand across a family mold can dramatically lower tooling cost. - No growth assumption: a 3-year ramp from 200 k to 800 k EAU is a very different mold than a flat 800 k from day one. Quote both scenarios. ## Related terms See also: cavity, clamp force tonnage, cycle time, estimated tonnage required, injection molding machine imm, shot weight. ## FAQ ### What does Annual Demand mean in injection molding? Annual Demand (EAU) is the number of identical parts a customer expects to consume in 12 months. It is the input molders use to size the cavitation, choose the SPI mold class, select press tonnage and target a cycle time that hits the price. ### What is EAU in plastic injection molding? EAU stands for Estimated Annual Usage — the North-American name for Annual Demand. An EAU above one million typically requires an SPI Class 101 tool; under 100,000 a Class 103 or 104 is usually enough. ### How do I calculate the number of cavities from Annual Demand? Multiply Annual Demand by the cycle time in seconds and divide by 3,600 × available press hours per year × OEE. Round the result up to the next mold-shop standard cavitation (1, 2, 4, 8, 16, 32, 48, 64). ### What is the difference between Annual Demand and lifetime volume? Annual Demand covers 12 months and drives cavities, tonnage and machine choice. Lifetime volume covers the whole program (typically 3–7 years) and drives the steel hardness and the cycle-count rating of the mold (SPI class). ### Is Annual Demand the same as forecast? Almost. A forecast is a probabilistic estimate over time; Annual Demand is the point figure (often an average) the molder commits the tool to. Good RFQs include a low/medium/high Annual Demand band, not a single number.

Lean Manufacturing is the systematic methodology to reduce the seven classic wastes (overproduction, waiting, transport, over-processing, inventory, motion, defects) in any production system. In injection molding it attacks press idle time, start-up scrap and long changeovers. ## Pillars of Lean in molding - Continuous flow: minimize inventory between press, secondary ops and packaging - Pull (kanban): produce only what the next customer requests - Jidoka (built-in quality): automatic scrap detection by vision or sensors - Standardization: start-up checklists, master parameters and SMED - Continuous improvement (kaizen): small daily improvements by the operator ## Common Lean tools in molding plants - 5S for orderly workstations and tool cribs - SMED to slash mold-change times (target <10 min) - Total Productive Maintenance (TPM) for machine availability - OEE (Availability × Performance × Quality) as the headline KPI - Andon: visible alerts for stops, scrap or changeovers ## Typical indicators - World-class OEE in injection molding: 85 % - Target mold-change time: <10 min (SMED) - Acceptable scrap: <1 % in stable production - Order-to-ship lead time cut by 40 – 70 % after implementation ## Common pitfalls Rolling out tools without changing culture, copying Toyota without adapting, chasing metrics (OEE) without attacking root cause, and abandoning 5S discipline at the first demand spike.

Preventive maintenance (PM) is the set of scheduled actions carried out on an injection molding machine and its auxiliaries to prevent breakdowns before they happen, instead of repairing after a failure. In an injection molding plant it is the single biggest lever on unplanned downtime and machine OEE. ## Why it matters An unplanned stop in the middle of a production run scraps parts, breaks the thermal steady state and can damage the mold. Planned maintenance is scheduled into low-demand windows, keeps the press repeatable, and extends the life of the screw, barrel and hydraulics. ## Preventive maintenance checklist for an injection molding machine | Frequency | Tasks | |-----------|-------| | Daily | Check oil level and temperature, water-circuit flow, hopper/dryer, safety gates and light curtains, clean the mold area | | Weekly | Grease tie-bars and toggle/clamp, inspect heater bands and thermocouples, check hoses and couplings for leaks | | Monthly | Hydraulic-oil analysis, clean oil cooler and filters, verify check-valve (non-return valve) seal, calibrate pressure and temperature sensors | | Annual | Inspect screw and barrel wear, replace seals, full hydraulic service, electrical-cabinet and PLC backup, geometry/parallelism check | ## Preventive vs. predictive vs. corrective maintenance - Corrective: repair after the failure — cheapest to plan, most expensive in lost production. - Preventive: fixed time- or cycle-based schedule — predictable, but can over-service parts that are still healthy. - Predictive (IIoT): sensors track vibration, oil condition and cycle data to service only when needed — the modern target for Industry 4.0 cells. ## What is preventive maintenance in injection molding? It is time- or cycle-based servicing of the molding machine, auxiliaries and molds — lubrication, inspection, calibration and part replacement — done on a schedule to stop failures before they cause unplanned downtime. ## What goes on a preventive maintenance checklist? Daily oil and water checks, weekly lubrication and heater-band inspection, monthly hydraulic and check-valve service, and an annual screw/barrel wear inspection with full seal replacement. ## What is the difference between preventive and predictive maintenance? Preventive follows a fixed schedule; predictive uses sensor data (vibration, oil, cycle counts) to service only when the data shows it is needed, avoiding both breakdowns and unnecessary work.