Micro Injection Moulding: Precision Micromolding Service
Micro injection moulding: parts from 0.001g to 1g with micron-level features. Medical, electronic, and optical micro components. Electric machine precision.
Micro Injection Moulding: Precision Micromolding Service
Micro injection moulding produces plastic parts weighing 0.001g to 1g with micron-level features. Using all-electric micro machines and precision micro molds, we manufacture medical, electronic, and optical components that conventional moulding cannot reach.
At FIRMFG, our micromoulding capability combines all-electric micro machines, micro plasticizing units, two-stage screw-plunger injection, and closed-loop control to hold tolerances of ±0.005mm on parts the size of a grain of rice. We mould features down to 10μm and inspect them with optical microscopes, vision systems, and micro CMM.
This guide covers micromoulding technology, material selection, micro mold design, quality inspection, and a comparison with standard moulding. Or, skip ahead and request a quote for an immediate price and lead time.
Micro Moulding Quick Specifications
Key specifications for micro injection moulding on all-electric micro machines.
| Specification | Value |
|---|---|
| Part Weight | 0.001 – 1 g |
| Min Feature Size | 10 μm |
| Tolerance | ±0.005 mm |
| Surface Roughness | Ra 0.1 μm |
| Shot Volume | 0.01 – 1 cm³ |
| Cycle Time | 5 – 15 s |
Micromoulding Technology
Specialized machines and systems that make reliable micron-level moulding possible.
All-Electric Micro Machines
All-electric micro injection machines deliver shot-to-shot repeatability under 0.1g with servodrive precision. No hydraulic fluctuation means consistent micro-part weight and dimensions across thousands of cycles.
Why it matters: Repeatability < 0.1g shot weight, ±0.005mm tolerance
Micro Plasticizing Unit
A dedicated micro plasticizing screw (8–15mm diameter) homogenizes tiny resin batches without thermal degradation. Small shot volumes mean short residence time and stable melt quality for heat-sensitive materials.
Why it matters: 8–15mm micro screw, short residence time
Precision Metering
Closed-loop metering doses exact shot volumes down to 0.01cm³. A separate injection plunger decouples plasticizing from dosing, eliminating screw backflow that would vary micro-part weight.
Why it matters: Dose to 0.01cm³, plunger injection
Screw/Plunger Design
Two-stage screw-plunger designs separate melt preparation from injection. The plunger transfers a measured dose into the cavity at high speed, ensuring complete fill of micron-scale features before freeze.
Why it matters: High-speed plunger fill for thin micro features
Closed-Loop Control
Closed-loop control of position, pressure, and velocity corrects in real time. Servo feedback adjusts each shot to hold critical micro-dimensions within ±0.005mm, essential for medical and optical parts.
Why it matters: ±0.005mm dimensional control, inline feedback
Material Selection for Micro Parts
Flow characteristics dominate material choice. Thin micro features demand high-flow thermoplastics.
| Material | Flow Characteristics | Best For |
|---|---|---|
| POM | Excellent flow, low friction | Micro gears, low-wear components |
| PEEK | Good flow at high temp, high strength | Medical implants, high-temp micro parts |
| LCP | Outstanding thin-wall flow, precision | Electronic connectors, mini connectors |
| PC (Polycarbonate) | Good flow, transparent | Optical micro lenses, clear housings |
| PA (Nylon) | Good flow, tough | Micro mechanical parts, snap-fits |
| PE / PP | Excellent flow, medical grade | Medical disposables, micro fluidics |
Micro Mold Design & Manufacturing
Micro molds demand specialized machining, hardened materials, and precise cooling and venting for sub-gram parts.
Micro EDM
Electrical discharge machining cuts micro cavities and features below 50μm with no mechanical force. Ideal for sharp corners, deep slots, and complex micro geometry that milling cannot reach.
Micro Milling
High-speed micro milling with 0.1mm cutters machines precision cavities and cores. Hardened steel and carbide tooling achieve sub-micron surface finishes on mould inserts.
Laser Machining
Laser ablation removes material at sub-micron resolution for venting channels, micro-textures, and feature refinement. Femtosecond lasers machine features without heat-affected zones.
Precision Inserts
Replaceable micro inserts let us machine cavities separately and assemble them into the mold base. Inserts enable multi-cavity micro tools and faster maintenance without rebuilding the whole mold.
Mold Material Selection
Hardened tool steel (SKD11, M2) and tungsten carbide withstand abrasive filled resins and maintain micro-feature integrity over long runs. Material hardness directly preserves micron-level detail.
Cooling & Venting
Micro cavities demand conformal cooling for uniform freeze and precise venting to evacuate trapped air. Poor venting causes short shots and burn marks on parts weighing fractions of a gram.
Quality Inspection for Micro Parts
Micro parts require specialized metrology — calipers cannot reach micron features.
Microscope Measurement
Optical microscopes measure critical micro-features at 100×–1000× magnification, verifying dimensions that conventional calipers cannot reach.
Vision Inspection Systems
Automated vision systems capture and dimension 100% of parts inline, rejecting out-of-tolerance components at production speed without human handling.
Micro CMM
Micro coordinate measuring machines probe 3D micro-geometry with sub-micron probes, validating complex features and GD&T on tiny parts.
Automated Sorting
Robotic and vacuum handling sort micro parts by cavity and quality without contamination, essential for medical and optical components.
Inline Inspection
Cameras and sensors inspect each shot inline, feeding data back to the moulding machine to auto-correct process drift before out-of-tolerance parts accumulate.
SPC for Micro Parts
Statistical process control tracks critical micro-dimensions across cavities and shifts, ensuring long-term capability indices meet medical and electronic requirements.
Design Guidelines for Micro Parts
DFM rules for flow, gating, venting, and demoulding at micron scale.
| Parameter | Guideline | Notes |
|---|---|---|
| Flow Length Ratio | ≤ 100:1 (thin walls reduce) | Micro gates need high-flow grades |
| Micro Gate Design | 0.1 – 0.3 mm gate | Submarine or edge gate; minimal vestige |
| Venting | 5 – 10 μm vents | Trapped air causes short shots and burns |
| Demoulding Method | Ejector pins or vacuum | Vacuum pickup for parts < 0.01g |
| Wall Thickness Limits | ≥ 0.1 mm | Below 0.1mm risks incomplete fill |
| Feature Aspect Ratio | ≤ 5:1 for cores | Higher ratios demould with difficulty |
| Tolerance | ±0.005 mm | ±0.002mm achievable on critical features |
Micro vs Standard Moulding Comparison
Micro moulding uses dedicated machines, molds, and metrology — not just a smaller standard process.
| Feature | Micro Moulding | Standard Moulding |
|---|---|---|
| Machine Type | All-electric micro machine | Hydraulic / servo standard machine |
| Mold Cost | $5,000 – $30,000 | $3,000 – $50,000+ |
| Part Cost | $0.05 – $2 (high volume) | $0.10 – $15 |
| Tolerance | ±0.005 mm | ±0.1 mm |
| Feature Size | 10 μm | 0.5 mm |
| Inspection Method | Microscope / vision / micro CMM | Calipers / CMM |
| Volume Suitability | 10,000 – 10,000,000+ | 1,000 – 1,000,000+ |
Micro moulding is not standard moulding scaled down. It requires all-electric machines, micro-feature mold machining, and microscope-grade inspection to hold micron tolerances.
Micro Moulding FAQ
Answers to the most common questions about micro injection moulding at FIRMFG.
QWhat is the minimum part weight you can mould?
We mould parts from 0.001g (1 milligram) up to 1g. Below 0.001g, material metering and demoulding become unreliable on standard micro machines. At 0.001–0.01g, we use plunger-type micro machines with vacuum demoulding. Most micro projects fall in the 0.05–0.5g range — small enough for micron features, large enough to handle and inspect. Send your CAD and we will confirm manufacturability at your target weight.
QWhat is the minimum feature size achievable?
We achieve features down to 10μm (0.01mm) — roughly the width of a human hair. Wall thickness down to 0.1mm is reliably filled; below that, flow length and venting limit fill. Micro features like channels, holes, and ribs can be 10–50μm wide with aspect ratios up to 5:1. Feature size depends on material flow, mold finish (micro EDM or laser machining), and part geometry. We verify critical features with optical microscopes and micro CMM.
QWhat materials can be used for micro injection moulding?
Most thermoplastics work, but flow characteristics dominate material selection. POM and LCP flow best into thin micro features. PEEK suits high-temperature and medical micro parts. PC provides optical clarity for micro lenses. PA (nylon) adds toughness for mechanical micro components. PE/PP are standard for medical disposables and microfluidics. Filled materials (glass/carbon fiber) are challenging at micro scale because fibers block thin features — we recommend unfilled or finely-filled compounds.
QWhat precision and tolerance can micro moulding achieve?
Standard micro moulding tolerance is ±0.005mm (5 microns). On critical features, closed-loop all-electric machines with optimized process control achieve ±0.002mm. Repeatability (shot-to-shot variation) is typically under 0.1% of part weight. Achieving these tolerances requires hardened steel molds, precision machining (micro EDM, micro milling), tight temperature control, and inline inspection with vision systems or micro CMM. Tolerance is feature-dependent — tightest on moulded dimensions, looser across parting lines.
QHow are micro parts inspected and measured?
Micro parts require specialized inspection. We use optical microscopes (100×–1000×) for dimensional measurement, automated vision systems for 100% inline inspection at production speed, and micro CMM with sub-micron probes for 3D GD&T verification. For high-volume medical and electronic parts, inline vision inspection rejects out-of-tolerance components automatically. Statistical process control (SPC) tracks critical dimensions across cavities and shifts to maintain long-term capability.
QHow much does micro injection moulding cost?
Micro mold cost is $5,000–$30,000 depending on complexity, cavities, and micro-feature machining (EDM, laser). Per-part cost ranges from $0.05–$2 at high volume — micro parts use little material and cycle fast (5–15s). At lower volumes (10,000 parts), mold amortization dominates. At high volumes (1,000,000+), per-part cost drops to cents. The economics favor micro moulding above ~10,000 parts; below that, micro machining or SLA may be cheaper. Request a quote for an exact price.
Applications of Micro Moulding
Micro moulding serves medical, electronic, optical, and fluidic industries where miniaturization is essential.
Medical Micro Devices
Surgical tips, catheter tips, and micro-valves
Micro Gears
Watch and instrument gear trains, micron pitch
Sensors
MEMS housings and enclosures for IoT
Optical Micro Lenses
PC lenses for cameras, fiber, and AR/VR
Electronic Connectors
LCP micro connectors for high-density boards
Micro Valves
Fluidic valves and pumps for drug delivery
Related Injection Moulding Services
Explore our other injection moulding capabilities.
Injection Moulding Service
Complete injection moulding services from prototyping to full production. Aluminum and steel tooling options.
Learn MorePrecision Injection Moulding
Precision moulding for tight-tolerance parts with ±0.05mm accuracy and quality inspection.
Learn MoreThin Wall Injection Moulding
Thin-wall moulding for lightweight parts with walls under 1mm and fast cycles.
Learn MoreStart Your Micro Moulding Project
Upload your CAD files and get a free micro injection moulding quote within 24 hours. Parts from 0.001g with 10μm features, ±0.005mm tolerance. Medical, electronic, and optical grade. ISO 9001 quality.