Mold Flow Analysis for Injection Molding
Know how the resin will fill your part before the steel is cut. Gate position, fill pattern, weld line location, air traps, pressure drop and predicted warpage across 40 resins, with a written report and 3D fill animation that you approve before tooling starts.
Free Consultation24h
Report Delivery
1 set
MOQ
12 types
Simulated Parts
40 grades
Resin Database
Materials
| Grade | Properties | Typical Applications |
|---|---|---|
| ABS and ABS-PC | Melt temperature 210 to 250°C, mould temperature 40 to 80°C, shrinkage 0.4 to 0.7%, moderate flow, sensitive to uneven wall thickness | Device housings, bezels, brackets, structural frames, snap-fit covers |
| Polycarbonate (PC) | Melt temperature 280 to 300°C, mould temperature 80 to 120°C, shrinkage 0.5 to 0.7%, high viscosity needs higher injection pressure, high residual stress | Clear covers, lenses, transparent enclosures, high-temperature components |
| PC/ABS Blend | Melt temperature 230 to 260°C, mould temperature 50 to 90°C, shrinkage 0.4 to 0.6%, better impact than PC with easier flow, a common electronics housing material | Laptop and tablet housings, monitor bezels, power tool bodies, consumer enclosures |
| Nylon PA6 and PA66 | Melt temperature 250 to 285°C, mould temperature 60 to 100°C, shrinkage 0.8 to 2.0% depending on fibre content, absorbs moisture before moulding | Structural brackets, clips, hinges, connectors, automotive interiors |
| PBT and PET | Melt temperature 240 to 280°C, mould temperature 40 to 90°C, shrinkage 0.3 to 0.6%, good dimensional stability, low warpage on flat parts | Connector housings, terminal blocks, precision gears, electrical insulators |
| Polypropylene (PP) | Melt temperature 200 to 240°C, mould temperature 30 to 80°C, shrinkage 1.0 to 2.5%, highest shrinkage of the common resins, floats and warps readily | Containers, clips, lids, packaging, low-load housings |
| POM (Acetal) | Melt temperature 190 to 220°C, mould temperature 40 to 90°C, shrinkage 1.8 to 2.5%, crystalline so it needs even cooling, excellent wear resistance | Precision gears, bushings, latches, snap hooks, mechanisms |
| PEEK and PEI (High Temperature) | Melt temperature 340 to 400°C, mould temperature 120 to 200°C, shrinkage 1.0 to 2.0%, requires heated tooling and careful moisture control | Medical and aerospace components, high-temperature electrical parts, semiconductor carriers |
Process Parameters
| Parameter | Standard Range |
|---|---|
| Report Turnaround | 24h for 2D, 48h for 3D fill animation |
| Simulated Part Size | up to 500 x 500 x 400 mm and 2.5 kg shot weight |
| Simulated Cavity Count | 1 to 32 cavities, balanced layout |
| Resin Database | 40 grades, 12 resin families |
| Melt Temperature Window | 190 to 400°C depending on resin |
| Mould Temperature Window | 30 to 200°C depending on resin |
| Predicted Linear Shrinkage | 0.3 to 2.5% depending on resin and fibre content |
| Predicted Warpage | reported as a vector map, not a single number |
| Weld Line Strength Impact | reported as a percentage of bulk strength |
| Gate Types Evaluated | Edge, side, submarine, valve, hot runner, multi-point |
| Analysis Depth (3D) | flow, temperature, pressure, velocity, shear rate, cooling, warpage |
| Deliverable Format | PDF report, fill animation, annotated STEP with gate and cooling recommendations |
Surface Finishes
VDI 3400 Texture (Grained Surface)
Chemically etched stainless steel cavity surfaces with a fine matte grain that transfers to the part. This is the standard cosmetic finish for visible housings, and the grain depth is specified as 0.025 mm per degree of draft angle required.
Gloss Polishing
Multi-step diamond polishing of the cavity to a mirror finish for transparent or glossy parts. The polish is applied before texturing if both are needed, and the DFM review flags areas where the polish will be lost in a textured zone.
Spray Texturing and Bead Blasting
Bead blasting with glass or ceramic media produces a uniform satin surface that hides tool witness marks and gives a consistent grip. Textures in this family have no draft angle requirement, which makes them a practical choice for draft-free walls.
Electro-polishing and Cleaning
Electrochemical polishing of the cavity surface removes micro peaks and reduces the risk of a polished part showing flow lines. A final cleaning cycle removes residual polish compound before the first shots, which is where contamination marks usually originate.
Hot Runner Integration
For multi-cavity tools or high-volume programs, a hot runner manifold with multiple drop points is specified so every cavity fills at the same rate. The simulation evaluates this layout against the same fill and temperature criteria as a cold runner tool.
Textured and Coloured Mould Steel
Mould base and cavity steel specified in the appropriate grade for the resin and cycle, with corrosion resistant grades for glass filled resins where sulphur release attacks unprotected tool steel over time.
Design for Manufacturing (DFM)
- Hold wall thickness variation below 25% of the nominal wall, because a step in wall thickness is the single most common cause of flow marks and weld line weakness
- Keep a constant wall of 1.0 to 1.5 mm on cosmetic visible housings, and add a 0.3 to 0.5 mm cosmetic wall on the surface that faces the user
- Design 2 to 3 degrees of draft on all walls that pull off the core, and never rely on a textured surface to compensate for a draft-free wall
- Move gate points away from cosmetic faces, because the gate vestige and the surrounding flow orientation mark are visible under raking light
- Avoid multiple gate points on one wall unless the part is large, because a second gate creates a second weld line and doubles the risk of a visible flow split
- Plan a shutoff and an air trap at the end of the fill path, since a trapped air pocket is a sink mark and a short shot on the last part to fill
- Specify cooling channels near thick sections and around bosses, because uneven cooling is what converts a filling problem into a warpage problem
- Use ribs at 50 to 60% of the nominal wall thickness, which keeps the flow path even and avoids a rib shadow on the opposite surface
- Locate ejector pins on bosses and thick sections rather than on cosmetic faces, and add a witness ring so the pin mark is hidden
- Upload STEP, IGES or DXF files and get a written simulation report within 24h with gate positions, fill time, pressure and cooling recommendations
Tooling & Capacity
| Type | Lead Time | Suitable For |
|---|---|---|
| Analysis Only (No Tooling) | 24h for 2D report, 48h for 3D animation | Design stage validation, quote support, gate location decisions before committing to steel |
| Aluminium Soft Tooling | 2 - 3 weeks | Pilot runs of 25 to 500 pieces, market validation, DVT builds |
| Steel Production Tooling | 4 - 6 weeks | Volume production above 50,000 pieces per year, or parts with tight cosmetic or dimensional requirements |
| Hot Runner Tool | 5 - 7 weeks | High-volume multi-cavity programs where runner scrap and cycle time dominate the cost |
Quality Assurance
- Resin data taken from the supplier datasheet for the specific grade, not a generic family value
- Fill time, peak pressure and clamp force reported as simulated values with the assumptions listed
- Weld line location and orientation marked on the part drawing with a predicted strength percentage
- Air trap and sink mark locations identified on the model with a suggested vent or shutoff position
- Warpage reported as a vector map with the direction and magnitude of movement at each critical feature
- Cooling channel layout recommended with the effect on cycle time stated in seconds
- Injection moulding DFM report delivered with the simulation, covering draft, walls, ribs, gates and ejectors
- First shot article report compared against the simulation to confirm the fill pattern matched the prediction
- SGS, Bureau Veritas or TUV inspection is arranged at any stage on request alongside the simulation work
- Dimensional report, material certificate and Certificate of Origin ship with every moulded lot from the analysis programme
Applications
- Consumer electronics housings and bezel components
- Automotive interior trim and structural parts
- Medical device enclosures and mounting brackets
- Packaging components and closures
- Appliance housings and control panels
- LED and lighting housings
- Connectors and terminal blocks
- Small appliance shells and handles
- Toys and consumer accessories
Why Choose FHY Precision
Resin data comes from the specific grade datasheet, so the simulation reflects your material rather than a generic average
Simulation runs before any steel is cut, so a gate that causes flow marks or warpage is found while it is still free to change
Written report within 24h for 2D analysis and 48h for 3D fill animation, with the assumptions stated so your engineer can challenge them
The same team runs the analysis and builds the tool, so recommendations and manufacturing practice do not drift apart
First shot article compared against the simulation, which catches the cases where the real fill did not match the prediction
Our documented quality system includes third-party inspection and EN 10204 3.1 mill certificates on request
Analysis run by the same China team that operates the press
A single purchase order covers analysis, tooling, trials and production parts
FAQ
1. What is mold flow analysis and what does it actually tell me?
It is a simulation of how molten resin fills your cavity. The software predicts the order in which the material reaches each region, where the front slows down, where two flow fronts meet and form a weld line, where air gets trapped, and how the part will distort as it cools. The output is a set of numbers and a set of marked locations, not a yes or no answer, and its value is that a bad gate position shows up on screen in an afternoon instead of on the machine after the tool is built.
2. How long does a mold flow analysis take?
A 2D report with gate recommendations, pressure, fill time and cooling commentary comes back within 24 hours of receiving the model. A 3D analysis with fill animation, temperature and shear rate fields, and a warpage vector map takes 48 hours because the mesh and the cooling solver need more computation. If you need the tool cutting in parallel with the analysis, that is possible, but we would recommend reviewing the fill result first, because a gate change after the steel is cut is an expensive change.
3. What do I need to send for the analysis?
A 3D model in STEP or IGES, the resin grade you plan to use, the target quantity per year, and any information about the cosmetic standard and the tolerance on flat parts. A 2D drawing helps for the tolerance callouts. If the resin is not decided, tell us the operating environment and the mechanical expectations, and we will run two candidate grades so you can see which one fills better and which one warps less.
4. Does the analysis guarantee the part will mould correctly?
No, and it would be dishonest to claim otherwise. A simulation is a model of the process, and it depends on the resin data, the assumed cooling and the mesh resolution. Its value is comparative: it ranks your design against alternative gate positions, wall structures and cooling layouts, and it identifies the failure modes you should watch for on the first shots. We compare the first shot article against the prediction afterwards, and that comparison is what turns the analysis into evidence.
5. How accurate is the warpage prediction?
Reasonably good in direction and rough in magnitude. The vector map reliably tells you which way the part will move and which feature moves most, which is what you need to decide where to add ribs or where to place a gate. The absolute millimetre value depends on the cooling assumptions and the fibre orientation in the resin, so we treat it as a ranking tool rather than a tolerance statement. Real warpage is verified by measuring the first article.
6. Can you simulate multi-cavity tools and hot runners?
Yes. The simulation balances the runner system and shows whether every cavity fills at the same rate and at the same temperature, which is the usual reason a multi-cavity tool has a scrap problem in the last cavity. For hot runners the drop point positions are evaluated the same way, with the added consideration that the melt must stay above the degradation temperature between drops, so the cycle time limit becomes visible before you order the manifold.
7. How much does mold flow analysis cost?
The 2D report and the 3D analysis are included with our tool quote, and they are free of charge when we build the tool. If you want the analysis as a standalone consulting deliverable for a tool you are building elsewhere, we quote it separately, and it covers the report, the annotated model and a call with your engineer to walk through the findings.
8. What happens if the analysis shows a problem with my design?
We tell you, and we tell you at the stage where a change is still cheap. Sometimes the fix is a gate move. Sometimes it is a wall thickness adjustment or a rib pattern change. Sometimes it is accepting a limitation and designing the cosmetic standard around it. We do not cut the tool on a design we know will flow badly, because the trial shots then become a paid experiment with your name on it.
9. Which resins do you simulate?
Forty grades across twelve resin families, including ABS, ABS-PC, PC, PC/ABS, PA6, PA66, glass filled PA, PBT, PET, PP, POM, PEI and PEEK. For unfamiliar grades we use the supplier datasheet for the specific grade you intend to buy, and if the datasheet is not available we tell you which properties we assumed. For high-temperature resins such as PEEK the analysis includes the heated tooling requirement, because the cooling assumptions are the difference between a usable result and a meaningless one.
10. How does shrinkage get handled?
Shrinkage depends on the resin, the fibre content and the direction of flow, and it is the reason a 0.3% resin and a 2.5% resin cannot share a tool. We use the grade-specific shrinkage value and report the linear and volumetric figures, then check the critical dimensions against the tolerance once the mould dimensions are fixed. Parts with tight tolerances across the flow direction need compensation in the tool, and the analysis tells us where that compensation has to go.
11. Is the analysis included if you quote the tool separately?
The standard mould quote includes the 2D report and the first shot verification, and the 3D animation with the warpage map is included on tool orders above 50,000 pieces per year or where the part has a flat cosmetic surface. If you are comparing suppliers, ask each one to show you the fill result for your own model. A supplier who quotes a tool without running the analysis is quoting on tooling cost alone, which is not the whole cost.
12. How long does the whole mould take after the analysis?
Aluminium soft tooling runs 2 to 3 weeks and is the right choice for 25 to 500 pieces. Steel production tooling runs 4 to 6 weeks and becomes the economical route above roughly 50,000 pieces per year. A hot runner tool takes 5 to 7 weeks. Trial shots and first article inspection are included in those figures, and the timing starts from the point where you approve the fill result and the design is frozen.
13. What information do you need to quote an analysis and a tool?
A 3D model in STEP or IGES, a 2D drawing with tolerances and cosmetic callouts, the resin grade and any fibre content, the annual volume, the number of parts you want per cavity, and the target cost per part if you have one. If the design is still moving, tell us which part numbers are frozen and which are not, so the analysis focuses on the parts that will actually go into tooling first.
14. Which software do you run the analysis in?
We use a commercial 3D solver for the fill and cooling work and a 2D calculation for quick gate and wall checks. The choice of software matters less than the inputs, and the inputs are where the accuracy is won or lost: the resin grade datasheet, the actual wall geometry, the cooling channel positions and the mould temperature. We state every assumption in the report so your own engineer can see exactly what was assumed and argue with it if needed.
15. Does the resin grade affect the tool steel you specify?
Yes, and it is a decision worth making early. Glass filled resins such as glass filled PA or PBT release sulphur during the run, and that attacks unprotected tool steel over time, so corrosion resistant mould steel is specified for those programs. High temperature resins such as PEEK or PEI push the mould well above 200°C, which puts a different grade and a different temper under the cavity. The analysis is the right place to identify this because it happens before the steel is ordered.
16. Do you offer third-party inspection?
Yes. We arrange inspection by SGS, Bureau Veritas or TUV at any stage you specify, from incoming material verification of the tool steel to pre-shipment dimensional and functional checks on the moulded parts. You receive a neutral report from an inspector you did not appoint, which is often what an end customer requires before accepting a first lot from a new supplier.