Zamak. You have surely held it in your hand already.
Locks, handles, hinges, hardware: you have probably touched it today. Here is what it is, what it is for and when it isn't.
What it is, plainly
Zinc, aluminium, magnesium and copper. Melted and injected into a die.
Zamak (zama in Italian) is a zinc alloy. It is injected into a steel die at a little over 400 °C: hot-chamber die casting. The part comes out precise, with a surface that is already excellent.
We mainly use zamak 5, the most widely used. In the European standard EN 12844 it is called ZP5. Others exist: we choose which on your part, not on a catalogue.
The alloys in numbers
Zamak 5 and zamak 3, side by side.
Zamak 5 is harder and stronger. Zamak 3 is more ductile. Same family, same way of working: what changes is the part you need to make.
| Zamak 5 · ZnAl4Cu1 | Zamak 3 · ZnAl4 | |
|---|---|---|
| Tensile strength | 330 MPa | 280 MPa |
| Yield strength | 295 MPa | 268 MPa |
| Elongation | 5% | 10% |
| Brinell hardness | 92 HBS | 83 HBS |
| Fatigue strength (10⁸ cycles) | 56 MPa | 48 MPa |
| Density | 6.7 kg/dm³ | 6.6 kg/dm³ |
| Melting range | 380–386 °C | 381–387 °C |
| Die-casting temperature | 400–440 °C | 400–440 °C |
| Thermal conductivity | 108.9 W/(m·K) | 113 W/(m·K) |
| Electrical conductivity | 26% IACS | 27% IACS |
| Linear shrinkage | 1.17% | 1.25% |
| Copper | 0.7–1.1% | 0.03% max |
Indicative values at 20 °C, from the alloy supplier's data sheet. Aluminium 3.8–4.2% in both. Which one we use, we decide on your part.
Why people choose it
Eight reasons. None of them magic.
Complex shapes
Ribs, bosses, undercuts: in one shot.
Tight tolerances
The part leaves the die close to final size: less machining after. Minimal tolerances straight from the die.
Excellent surface
Smooth and suited to nickel, chrome and zinc plating.
Thin walls where aluminium struggles
Fine details and low thickness, where plastic struggles.
Weight you can feel
A zamak part gives an impression of quality.
The look you want
Zinc-plated, nickel-plated, chrome-plated, painted: zamak can look the way you want.
Lasting
Raw or with surface treatments, zamak stays.
Recyclable
100% recyclable, the environment says thanks
When it doesn't pay off
Others always say yes. We also say no.
- Few parts. The die weighs on the cost: you need a quantity that pays it back.
- High, prolonged temperatures. It loses 40% of its mechanical properties above 200 °C.
- Very large parts. Beyond a certain size it isn't the right process.
- Where weight is a problem. Zamak is heavier than plastic and aluminium.
Zamak, plastic, aluminium
The comparison, no cheering.
| Zamak | Plastic | Aluminium | |
|---|---|---|---|
| Precision | High, straight from the die | Medium: shrinkage must be managed | Medium as cast, needs machining, at extra cost |
| Surface | Excellent, ideal for nickel, chrome and zinc plating, and painting | Good, but it isn't metal | Good, needs treatment |
| Weight | Heavy | Very light | Light |
| Strength and wear | High | Depends on type, sometimes gives in | High |
| Heat | Medium | Depends on the polymer | High |
| EMI shielding | Yes | No, without treatments | Yes |
| Recyclable | Yes | Depends | Yes |
General guidance: every part is its own story.
The test
Is your part a good candidate?
Four questions, one minute. An honest answer, not a quote.
Good candidate. With these numbers and these problems, zamak usually pays off. Next step: look at your part.
Bring us the partWorth checking. It can work, but it depends on shape and quantity. Send us the part: we'll tell you with numbers in hand.
Ask for our opinionDifficult. With this data the die may not pay for itself. If you think something is missing, write to us: we'll tell you anyway.
Write to us anywayWatch the heat. If the part runs at high temperatures for a long time, zamak is not the right choice. If your case is unusual, let's talk.
Let's talkGeneral guidance. Not a quote.
Zamak questions
Zamak or aluminium?
If you want a part that comes out of the die already "finished": precise, repeatable, needing little machining to match the drawing, and able to take almost any surface treatment (painting, chrome, zinc, nickel plating and more), zamak. If you need light weight, or the part must withstand high temperatures and you can afford higher machining costs, aluminium. We decide on the part, not on principle.
Zamak or plastic?
If plastic breaks, wears, gives in to heat or just feels cheap, zamak deserves a look. If the part is large, light and made for a few cents, plastic stays.
When does zamak pay off?
When you need a complex, precise part with a good finish, in a quantity that pays back the die. The test above gives you a first indication in a minute.
Is there a minimum order?
No, there is no minimum order. Every production run has a set-up cost (mounting and removing the die, entering the parameters, starting up) of 150 to 400 euro: the more parts you make, the less it weighs on each one. Zamak generally pays off from a few thousand parts a year upwards, but that is not a rule: it depends on you and on what you want to achieve.
Does zamak rust?
No, like aluminium it passivates itself. With nickel, chrome or zinc plating it resists much better; without treatment it depends on the environment. If the part works in an aggressive environment, we choose together.
Is zamak recyclable?
Yes. Scrap and end-of-life parts are remelted and go back into the production cycle. 100% recyclable.