Close mould (lock tool)
The two halves of the mould are closed and held tightly with high clamping force. This ensures the mould stays sealed and stable during injection.
Production Service
Die Casting
How are precise metal components produced by die casting, and when does the method become economically viable? Here you will find essential information on the process, hot- and cold-chamber techniques, typical metals (e.g. aluminium, zinc, magnesium), quality, post-processing, and cost considerations. Especially suited for medium to high volumes: assemblean supports you from feasibility studies through reliable execution via qualified manufacturing partners.
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Service overview
What is Die Casting?
Die casting is a process where molten metal is forced under high pressure into a precise metal mould (die casting mould) and solidifies there. The mould is clamped with high force, allowing even complex geometries to be reproducibly produced—often with short cycle times.
Typical strengths of die casting include excellent series production capability (efficient manufacture from medium to high volumes), often high dimensional accuracy and repeatability, as well as surface finishes that can be used directly or enhanced by post-processing/coating. Die casting is not a "material" but a process: depending on the application, aluminium, zinc, or magnesium alloys are commonly used.
In contrast, permanent mould casting (kokill casting) typically involves low or no injection pressure into a metallic permanent mould, resulting in different filling mechanics and solidification conditions. This affects properties such as porosity and surface finish depending on the component.
Investment casting often involves longer lead times and higher piece costs but is also used for series production.
Generally, "casting" refers to methods where metal is poured into a mould and solidifies. "Die casting" is a special casting variant where the mould filling occurs under high injection pressure, typically with metallic permanent moulds and high series capability.
Guide
How does die casting work? Process in four steps
In die casting (using the cold-chamber example), molten metal is pressed into a closed mould where it solidifies and is subsequently removed as a raw part. The typical process consists of four steps:
Comparison
Hot-Chamber vs Cold-Chamber Die Casting
| Criterion | Hot-chamber die casting | Cold-chamber die casting |
|---|---|---|
| Typical metals | Mainly zinc and, in some cases, other low-melting alloys | Mainly aluminium, plus magnesium and copper alloys |
| Principle | The injection system sits in the melt bath; metal is taken directly and injected | The melt is held in a separate furnace, dosed into the shot chamber, and then injected |
| Cycle time | Usually very short with high output | Typically longer because of the extra dosing step and higher temperatures |
Why Hot-Chamber is Common for Zinc and Cold-Chamber for Aluminium
Hot-chamber means the injection system is immersed directly in the molten metal. This greatly enhances productivity by allowing quick, stable dosing without external transfer.
For this to work reliably, the molten metal must be compatible with the unit's components (e.g. plunger, injection chamber) to avoid corrosion or excessive wear.
Zinc alloys, which have lower melting points than aluminium, are well-suited to hot-chamber systems, resulting in short cycle times, excellent reproducibility, and often very high surface quality.
Process
4 Simple Steps to Your Product
A clear flow, one point of contact, and a well-coordinated manufacturing process.
1
Submit Product Data
Request your quote online or via email. We review your drawings and technical data.
2
DFM Feedback
If desired, we provide feedback on die casting design. Together, we work on the best manufacturable solution.
3
Receive Quote
Once the final design is set, you receive a conclusive offer for your order.
4
Manufacturing, Quality Control & Delivery
assemblean manages the entire manufacturing process, performs quality control, and delivers your parts to the requested location.
Materials in Die Casting
Non-ferrous metals dominate die casting. Suitable alloys depend on component requirements like weight, strength, dimensional accuracy, surface, corrosion resistance, quantity, and cost. Aluminium, zinc, and magnesium are the most common.
We also offer stainless steel, brass, and silicon tombac. Need a specific alloy not listed? No problem— we collaborate to produce your parts in your desired material.
Aluminium
Aluminium offers very high thermal conductivity, process stability, and excellent corrosion and weather resistance. Aluminium die casting enables complex parts with thin walls. Common alloys include:
- AC-43400 / AlSi10Mg(Fe)
- AC-44300 / AlSi12(Fe)
- AC-46500 / AlSi9Cu3
Magnesium
Magnesium alloys have lower hardness and strength than comparable aluminium alloys, with high elongation and good castability. Due to heat resistance, they are used especially in automotive engine compartments. Common alloys are:
Why choose assemblean's die-cast parts? Benefit from these advantages
Unlimited Material Selection
Custom parts from your chosen material — we procure all materials and alloys you require.
Custom Surfaces
We offer a wide range of surface treatments tailored to your design and functional requirements.
A Personal Contact
As your reliable partner, we handle the entire order from tooling, production, to timely delivery of your die-cast parts.
Post-Processing
For finishing and wear and corrosion protection, we provide various surface treatments including:
- Painting
- Anodising
- Powder Coating
- Enamelling
- Sandblasting
- Polishing
- Grinding
- Brushing
- Heat Treatment
- Chromating
- Galvanising
References
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Examples
Typical Applications & Examples of Die Cast Parts
Die casting is used where series-capable metal components with good repeatability, stable quality, and economic production are required. Depending on material (aluminium, zinc, magnesium), component geometry, and surface or tolerance demands, die casting suits diverse products. Typical, neutral examples include:
Housings & Covers
e.g. electronic housings, protective covers, or functional enclosures where dimensional accuracy, stability, and clean surface appearance are critical.
Quality, Tolerances & Typical Defects
Die casting can produce highly reproducible results; however, dimensional accuracy, surface finish, and scrap rate strongly depend on component design, tooling, and stable process parameters. Typical defect patterns should be understood early and addressed design- or process-wise:
Porosity / Shrinkage Cavities (voids within the part)
Cause: Entrapped air/gas or shrinkage cavities during solidification, often influenced by venting, gating and overflow design, wall thickness transitions, and solidification direction.
Countermeasure: Optimise gating, runners, and venting; adjust process parameters (fill speed/pressure/temperatures); and apply design improvements such as more uniform wall thickness or targeted feeding and solidification control.
Die Casting Surfaces & Post-Processing
Many die cast parts are usable as-cast, but post-processing and surface finishing are key depending on functional and aesthetic requirements. Typical steps include deburring/removing gating for safe handling and assembly, blasting or tumble finishing for uniform surface appearance, and mechanical processing such as drilling, reaming, or threading to ensure functional surfaces and fits.
For appearance and protection, painting or powder coating, and other corrosion protection coatings are common—especially for moisture, outdoor use, or aggressive environments.
When Are Which Surface Finishes Appropriate?
Coatings or paint finishes can be organised through qualified partners if needed.
- Function first (fits/sealing surfaces/threads): targeted mechanical processing on relevant areas.
- Appearance/uniformity: blasting or tumble polishing; optionally followed by paint or powder coating.
- Corrosion-sensitive environments: early integration of coating/corrosion protection considering material, usage environment, and specification.
Guide
Costs & Economics in Die Casting
Die casting becomes cost-effective when tooling costs are amortised over an appropriate volume and the process runs stably in series. Unit costs decrease with volume since many efforts (tooling, process setup, sample approval) are initial fixed costs distributed over the production run.
Key Cost Drivers
Tool / Mould
Tooling, mould making, and potentially slides/mechanics are usually the largest upfront cost. Complexity increases initial cost.
Comparison
Die Casting vs Injection Moulding Overview
| Criterion | Die casting | Injection moulding |
|---|---|---|
| Material | Metals such as aluminium, zinc, and magnesium | Plastics, both thermoplastics and thermosets |
| Temperature and process | Molten metal is processed in metallic tooling | Molten plastic is processed in temperature-controlled tooling |
| Tooling and investment | Tooling is designed for high thermal and mechanical loads | Tooling focuses on material flow, cooling, and demoulding |
FAQ
Frequently Asked Questions about Die Casting (FAQ)
What is Die Casting?
Die casting is a casting method where molten metal is pressed under high pressure into a metallic mould and solidifies there. This allows for series-production metallic parts with good repeatability and often excellent surface finish.
Hot-Chamber or Cold-Chamber—What is the Difference?
Hot-chamber die casting has the injection system in the melt, enabling very short cycle times. Cold-chamber die casting holds the melt separately and fills the casting chamber in portions—commonly standard for aluminium.
Which Metals are Typically Used in Die Casting?
Most frequently aluminium, zinc, and magnesium. Aluminium is a versatile all-rounder, zinc suits precise parts with excellent surface finish, and magnesium is suited for lightweight constructions.
Why Do Shrinkage Cavities or Porosity Occur?
Porosity/shrinkage cavities usually arise from trapped air/gases or shrinkage during solidification. Key factors include venting, gating and overflow design, process settings, and a design with uniform wall thickness.
Guide
Other Processes at a Glance
Knowledge hub
More Knowledge About Die Casting
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What Are the Most Important Die Casting Design Guidelines?
Die casting is a highly economic process for mass manufacturing metallic cast parts. It allows the production of complex shapes with high accuracy, thin walls, and smooth surfaces, which only [...]
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