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Rolvsøy Metallindustri

Thin walls, complex geometry and seconds per shot — in recycled aluminium.

Aluminium die casting

High pressure die casting in aluminium alloy for brackets, housings and fittings in series. The process behind most of the parts we make.

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Pressure die casting · aluminium

Aluminium die casting in Norway

Aluminium die casting in Norway, in one sentence: molten aluminium is forced into the steel die under high pressure and freezes in seconds. The process gives thin walls, complex geometry and a repeatability where part number 40,000 matches part number one.

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The process

What aluminium die casting is

Aluminium melts at 660 °C and is cast here at 680–700 °C. The melt is dosed into a shot sleeve and forced under high pressure into a high-alloy steel die. The cavity fills in a fraction of a second. The metal freezes against the cooled steel, the die opens, and ejector pins push the part out.

Then comes the operation most often underestimated in a costing: degating. Runner, overflows and flash have to come off. That is manual work, and it is one of the five things that decide what the part costs. A die that is well gated from the start, and a part drawn with deflashing in mind, saves that cost on every single part for the life of the series.

The feedstock is secondary aluminium — remelted metal from car parts, beverage cans and facade products — supplied as ingot from Metallco at Toten in Norway, realloyed to full casting specifications against international standards. Remelting takes a fraction of the energy of primary production. That is the single largest item in the carbon footprint of a cast aluminium part, and it sits in the raw material, not in the factory.

Suitability

When aluminium die casting is right — and when it is not

Choose aluminium HPDC when

  • Weight is a cost in the product. 2.7 g/cm³ is roughly a third of steel.
  • The geometry is complex: ribs, bosses, channels and mounting lugs in one part, that would otherwise be welded up from several pieces.
  • Walls are thin and volume is high. Cycle time is measured in seconds, not minutes.
  • The part is to be anodised or powder coated.
  • Corrosion resistance without a coating is an advantage.
  • The part has to be recyclable as metal at end of life.

Choose something else when

  • The part must be heat treated to reach its strength requirement. Pressure die cast parts normally are not heat treated — entrapped gas expands and blisters. Then gravity casting is the route.
  • The detail is very fine, or the wall has to be thinner than aluminium manages. Then zinc is better.
  • The series is below a few thousand parts a year. The tooling cost does not carry.
  • The part can be folded from flat sheet without losing function.
  • The part is large and heavy and needs sections a die casting machine is not sized for.

Example

Pressure tightness and a bearing fit — straight from the die

One of the brackets we make for the garden equipment industry is die cast in aluminium with critical tolerances for a bearing fit and for pressure tightness — and it is finished when it leaves the casting machine.

No subsequent machining at all.

That is worth dwelling on, because it contradicts a common assumption: that cast parts always have to be machined on the critical faces. Often true, but not always. Get the die, the gating and the process right from the start, and pressure die casting can hold tolerances that would otherwise cost a setup in the CNC machine.

This is one of the things the design review actually settles. Every face held as cast is one operation saved per part — across many thousand parts a year.

Read about the design review

Datablad

Specifications — aluminium die casting

Two of five fields we can document today. The other three are figures we know internally but have not verified for publication. Call, and you will get them.

Machine park

Processes in house
Pressure die casting (aluminium and zinc), gravity die casting, CNC turning, CNC milling, boring, heat treatment, blasting
Processes we do not have
Sand casting, toolmaking, anodising, powder coating
CAM software
Autodesk Fusion 360
Number of die casting machines
Available on request
Clamping force
Available on request
Hot or cold chamber
Available on request
Maximum shot weight
Available on request
Platen size and maximum die height
Available on request
Gravity casting stations
Available on request
Maximum mould size, gravity
Available on request
Melting furnaces and melting capacity
Available on request
CNC lathes
Available on request
Maximum turning diameter and length
Available on request
CNC mills
Available on request
Milling work envelope
Available on request
Boring machine
Available on request
Heat treatment furnace
Available on request
Blasting equipment
Available on request
Automation
Available on request
Machining operations
CNC turning, CNC milling, boring, tapping, sawing, grinding
Machining experience
More than 30 years år
Number of axes, milling
Available on request
Heat treatment applies to
Gravity die cast aluminium parts
Heat treatment — effect
Higher tensile strength and higher ultimate strength
Tempers we run
Available on request
Blasting
In house
Anodising
Via subcontractor — aluminium only, zinc cannot be anodised
Powder coating
Via subcontractor
Finishing subcontractors
Available on request
Die ownership
The customer owns the tool. We procure it, specify it for our machines and maintain it.
Typical tooling cost
Available on request
Die life, aluminium
Available on request
Die life, zinc
Available on request
Storage and insurance of customer-owned dies
Available on request
Shift pattern
Available on request

Alloys

Metals
Aluminium and zinc
Feedstock form
Ingot from established suppliers
Aluminium supplier
Metallco, Toten, Norway — secondary aluminium realloyed against international standards
Aluminium melting point
660 °C °C
Aluminium casting temperature
680–700 °C °C
Alloy selection
Made together with the customer, as part of the design review
Aluminium alloys, pressure die casting
Available on request
Aluminium alloys, gravity
Available on request
Zinc alloys
Available on request
Customer-specified alloy
Available on request
Material certificate
Available on request
Melt and batch traceability
Available on request
Recycled content
Available on request

Part sizes

Part weight
From a few grams to several kilos Estimat
Maximum part envelope
Available on request
Maximum projected area
Available on request
Minimum wall thickness, aluminium
Available on request
Minimum wall thickness, zinc
Available on request
Minimum wall thickness, gravity
Available on request
Minimum draft angle
Available on request
Minimum cored hole
Available on request
Insert casting
Available on request
Multi-cavity tooling
Available on request

Further down the chain

The next links

CNC machining

Faces and holes needing tighter tolerances than casting delivers.

Surface finishing

Blasting here, anodising and powder coating at a subcontractor.

Gravity die casting

The alternative when the part must be heat treated or the series is smaller.

Send the drawing

An answer within 24 hours. An estimate on a sketch, a formal quotation on final files.

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Henger sammen med

Zinc die casting

Thinner walls, sharper detail, longer die life — and almost no Norwegian suppliers.

Gravity die casting

Lower tooling cost, smaller series — and the only route to heat treated strength.

Heat treatment

Where the strength comes from — when casting alone is not enough.

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