Setting up a die casting furnace is not about turning a dial to a number on a chart. It is about matching the furnace to the alloy, the die, the machine, and the part. Get it right, and you produce consistent castings shift after shift. Get it wrong, and you fight porosity, cold shuts, and scrap forever.
I have spent 25 years setting up and troubleshooting die casting furnaces in China, Southeast Asia, India, the UK, Europe, and North America. In this article, I will walk you through exactly how I approach furnace parameter setup for high-pressure die casting. Not theory. Just the steps I take on the shop floor.
Start with the Alloy, Not the Furnace
Before you touch the furnace, know your alloy. A380 and ADC12 are the two most common die casting alloys. They look similar on a spec sheet. They behave differently in a furnace.
| Property | A380 | ADC12 |
|---|---|---|
| Silicon content | 7.5–9.5% | 9.6–12.0% |
| Liquidus temperature | ~593°C | ~580°C |
| Recommended holding furnace temperature | 680–700°C | 660–680°C |
| Recommended metal at shot sleeve | 670–700°C | 650–680°C |
The 20°C difference in liquidus temperature translates directly to a 20–30°C difference in furnace setpoint. If you run A380 at ADC12 temperatures, you will get cold shuts. If you run ADC12 at A380 temperatures, you will get gas porosity and oxidation.
I once visited a plant in Guangdong that ran both alloys on the same holding furnace. They changed alloys twice per week but never changed the setpoint. Their rejection rate was 11%. We set up two recipes on the controller — one for A380 at 690°C, one for ADC12 at 665°C. The rejection rate dropped to 3.4% within two weeks.
Step 1: Set the Holding Furnace Temperature
The holding furnace is where the metal waits before it goes to the shot sleeve. Its temperature determines the metal temperature at the shot sleeve. That is the number that matters.
I use this rule: set the holding furnace 20–30°C above the target shot sleeve temperature. The metal loses heat during transfer and in the ladle. If you want 680°C at the sleeve, set the furnace to 700–710°C.
For A380 with 2.5 mm walls, I set the holding furnace to 690–700°C. For thicker walls (5–8 mm), I lower it to 680–690°C. For ADC12, subtract 20°C.
But do not trust the controller display. Verify with a handheld immersion pyrometer at the shot sleeve. I have seen controllers read 700°C when the metal at the sleeve was 650°C. That 50°C difference is the difference between a good part and scrap.
Step 2: Verify Temperature Uniformity
A furnace can have the correct setpoint but poor uniformity. The metal near the heating elements is hotter than the metal near the door. This causes inconsistent fill and localised defects.
I use a thermal camera or multiple thermocouples to map the temperature across the bath. If I see more than 10°C variation, I improve circulation or add a second thermocouple. For critical parts, I target ±5°C across the bath.
In one foundry in Thailand, the holding furnace had a single thermocouple in one corner. The metal near the door was 25°C cooler. We added a second thermocouple and repositioned the first. The controller now averages the two readings. Temperature stability improved from ±15°C to ±4°C. The scrap rate dropped by half.
Step 3: Set Dosing Parameters
For automatic dosing furnaces, the dosing parameters determine shot weight consistency. The key parameters are:
| Parameter | Recommended Setting |
|---|---|
| Dosing pressure | 0.3–0.5 bar (adjust for alloy) |
| Dosing time | 1.5–3.0 seconds |
| Shot weight tolerance | ±1% for structural parts, ±2% for commercial |
| Metal level in dosing chamber | Maintain consistent level |
I always run a shot weight study before production. Weigh 20 consecutive shots. If the variation is more than ±2%, adjust the dosing pressure and time. For EV structural parts, I target ±1%.
A foundry in Malaysia was running a manual ladle. Shot weight varied by ±4%. That caused flash on some shots and cold shuts on others. We installed an electric dosing furnace with ±1% accuracy. The rejection rate dropped from 8% to 2.3%.
Step 4: Set Degassing Parameters
Gas porosity is the enemy of die casting. Hydrogen must be removed before the metal reaches the shot sleeve.
For rotary degassing, I use these parameters:
| Parameter | Recommended Range |
|---|---|
| Rotor speed | 500–700 rpm |
| Argon flow rate | 15–25 L/min |
| Degassing time | 8–12 minutes per batch |
| Gas purity | ≥99.99% argon |
I measure hydrogen before every pour. The target for structural die casting is below 0.15 ml/100g Al. For general commercial castings, below 0.25 ml/100g is acceptable.
If hydrogen is above target, I increase degassing time. If it is below, I reduce it. Measurement is not optional. Without it, you are guessing.
Step 5: Set Shot Sleeve Temperature
Most foundries focus on the furnace. Few pay attention to the shot sleeve. That is a mistake.
A cold shot sleeve causes chill layers to form on the metal surface. These chill layers break off during injection and cause turbulence, porosity, and cold shuts. Research on shot sleeve temperature in aluminium HPDC found that at a sleeve temperature of 280°C, chill layer formation is minimised, trimmed surface quality is best, and casting density is highest.
I preheat the shot sleeve to at least 200°C before production. For critical parts, I target 250–280°C. If your sleeve is running cold, the best furnace temperature in the world will not save you.
Step 6: Set Vacuum Parameters
For structural parts, vacuum-assisted die casting is standard. The vacuum level determines how much air is removed from the cavity before the metal enters.
| Part Type | Recommended Vacuum Level |
|---|---|
| General commercial | Below 200 mbar |
| Structural / EV | Below 100 mbar |
| Leak-tight / safety-critical | Below 50 mbar |
I check the vacuum seals weekly. A leaking door seal ruins the vacuum. In one foundry, the vacuum level was 180 mbar. We found a leaking seal on the die casting machine. We replaced it. Vacuum dropped to 85 mbar. The leak test rejection rate dropped from 9% to 1.8%.
Step 7: Set the Fast Shot Speed
The fast shot speed determines how quickly the metal fills the cavity. Too slow, and the metal freezes before filling. Too fast, and the flow becomes turbulent, creating air entrapment.
Research on process parameters found that increasing the fast shot speed reduced the equivalent diameter and number of shrinkage and gas-shrinkage pores, while also reducing gas pore quantity.
But there is a limit. Past a certain speed, the flow becomes chaotic. The metal splashes. Air is trapped regardless of vacuum.
I tune the fast shot speed on every die. Start conservative. Increase until you see the first sign of turbulence on the surface. Back off by 10%. That is your setpoint.
A Real Case from Guangdong
In 2024, a die casting plant in Guangdong was producing motor housings for an EV OEM. Their leak test rejection rate was 9%. The defects were gas porosity.
We measured hydrogen in the holding furnace. It was 0.31 ml/100g Al. The target was 0.15.
The plant was using manual lance degassing. No measurement. No control.
We installed a rotary degasser with argon. We set the parameters: 650 rpm, 20 L/min argon, 8 minutes per 500 kg batch. We trained the operators to measure hydrogen before every pour.
We checked the vacuum system. The vacuum level was 180 mbar. We found a leaking door seal on the die casting machine. We replaced it. Vacuum dropped to 85 mbar.
We increased the fast shot speed by 8% and adjusted the switch point.
Results after one month:
| Metric | Before | After |
|---|---|---|
| Hydrogen content | 0.31 ml/100g | 0.12 ml/100g |
| Vacuum level | 180 mbar | 85 mbar |
| Leak test rejection | 9.0% | 1.8% |
The annual saving was over $210,000. The investment was $11,500. Payback was under three weeks.
A Simple Furnace Parameter Setup Checklist
Know your alloy. A380 and ADC12 need different setpoints.
Set holding furnace 20–30°C above target shot sleeve temperature.
Verify metal temperature at the shot sleeve, not just the furnace.
Check temperature uniformity. Target ±5°C across the bath.
Set dosing parameters. Target ±1% shot weight for structural parts.
Set degassing parameters. Measure hydrogen before every pour.
Preheat shot sleeve to at least 200°C.
Set vacuum level based on part type. Below 100 mbar for structural.
Tune fast shot speed. Start conservative, increase until turbulence appears.
Record everything. You cannot improve what you do not measure.
Final Thoughts
Setting up a die casting furnace is not about turning a dial to a number on a chart. It is about understanding the relationship between alloy, temperature, dosing, degassing, vacuum, and shot profile.
In my 25 years, I have seen foundries transform their quality by doing nothing more than getting the furnace parameters right. It is the simplest fix. It is also the one most often overlooked.
If you are fighting quality problems, start with the furnace. Measure the metal temperature at the shot sleeve. Check hydrogen. Check vacuum. Then adjust the parameters. You will find the cause.
Internal links: How to Optimize Die Casting Furnace Temperature for A380 and ADC12 Alloys, How to Reduce Gas Porosity in Die Casting Aluminium Melts, Case Study – How a Chinese Expert Optimized Die Casting Furnace for EV Part Production
About the Author: Hu Shenyue is a veteran aluminium melting furnace expert with 25 years of hands-on experience in China, Southeast Asia, India, the UK, and Europe. He writes practical, experience-based content on furnace selection, maintenance, and optimisation at SmeltPro.
