Medical equipment die-casting is a manufacturing process. Manufacturers use this technique to create high-quality metal components. That are widely used in medical devices. In die casting, they melt the material and pour it into the mold cavity under high pressure. This process creates intricate and complex parts with precise dimensions and tolerances.

In this article, you will learn die-casting techniques used for medical equipment production. Also, we have discussed its suitable material, applications, and design recommendations in detail.

Types of Medical Equipment Die Casting Techniques

Trykstøbning med varmt kammer

During hot chamber die casting, manufacturers use a crucible. This tool holds and transfers molten metal to the machine. They inject this material directly into the mold using an injector and plunger.

hot chamber die casting process

The entry port mounted to the machine allows this metal to flow into the cavity. Manufacturers usually use this process when working with low-melting metals like zinc. They melt this metal at temperatures of 380-420°C (716-800°F). And use pressures of 10-100 MPa (1450-14500 psi). The process takes around 1–5 minutes to complete, one cycle per unit.

Trykstøbning i koldt kammer

Manufacturers use a separate ladle during Trykstøbning med koldt kammer. They use it to feed molten metal into a chamber. This is done before a plunger forces it into the mold. The crucible stays outside the machine. They reduce heat and protect parts from damage.

Cold Chamber Die Casting Process

You can use this processing if creating medical parts with those high-melting metals. For example, aluminum metal is operated at temperatures of 500-700°C (932-1292°F) with pressures of 10-300 MPa (1450-43500 psi). The cycle time of the cold chamber process is around 2-10 minutes.

Die Design for Medical Equipment

Die design is important for getting strong and precise casting outputs. You must be sure the chosen die allows the liquified metal to move freely and cool quickly. In addition to this, try to maintain a metal flow rate between 0.1-10 kg/s (0.22-22 lbs/s).

Similarly, cooling channels for solidification must range from 1-100°C/s (1.8-180°F/s). Because your good die designs reduce defects like cracks and air pockets. They can also improve the toughness and looks of the finished part.

How Much Heat Can a Die Withstand?

Generally, manufacturers make high-strength dies. These dies can handle temperatures of 150-300 °C (302-572 °F). They can produce accurate castings using these dies.

Manufacturers commonly select strong materials like hardened steel with a hardness of 40-60 HRC (Rockwell Hardness Scale). This makes dies durable for repeated use.

They also add features like ejector pins for simple casting removal. These pins may exert forces of 1-100 kN (225-22,480 lbf).

Moreover, well-designed dies can last for 10,000–100,000 uses. However, it totally depends on the material and how it is used.

Incorporating Features

Engineers add various features to die casting during production. For example, they built cooling channels with diameters of 5-20 mm (0.2-0.8 inches) into the die. These channels improve cooling efficiency during operations. Also, they maintain cooling rates of 1-100°C/s (1.8-180°F/s).

Further, inserts such as threaded parts or bushings are also placed in the dies. This addition is done before casting.

Manufacturers use common insert sizes ranging from M4 to M12 threads or bushings with diameters of 10-50 mm (0.4-2 inches). These inserts produce accurate-shape parts and avoid the need for machining later.

Metallurgy

Die casting needs certain metallurgical properties. The grain structure of the metal causes damage to its strength. For example, if you maintain fine grains with sizes below 10 micrometers, it makes parts stronger. These parts also do not crack.

Porosity in parts is often caused by air passage or shrinkage. This is not good for part strength and may weaken it up to 30%. To avoid this, maintain a controlled temperature, such as for aluminum, around 650 °C.

Also, use pressures of 1500 to 3000 psi. Additionally, applying rapid cooling techniques cuts defects by over 50%. These channels ensure uniform solidification and reduce stress.

Shot Weight and Lubricants

Generally, shot weight is the amount of molten metal. That manufacturer uses for one casting cycle. It typically depends on the part’s size and often ranges from 50 grams to 50 kilograms (0.1 to 110 lbs).

Measure shot weight via a digital scale or an automated dosing system. That way you can ensure precision. The correct shot weight must match die cavity volume. Because die casting includes overflow reservoirs. So ensure the part fills completely without waste.

Design Considerations

Manufacturers focus on adding round edges and smooth transitions for medical device die-casting. These shapes avoid cracks and ensure strength. For instance, they try to maintain a uniform thickness of around 1.5–3 mm at joints. So that these joints do not unfasten.

Also, avoiding tight corners, sharp edges, and irregular shapes reduces defects and trimming costs. Because simple, smooth designs improve casting quality, reliability, and accuracy. They further ensure parts meet stringent medical standards.

Lubricants and Release Agents

Lubricants and release agents make your part removal process smoother. For this, you should spray or brush them onto the die surface before casting.

You can try both methods—automatic spray systems or manual. Particularly, the automatic use of about 0.1-0.5 liters (3.4-17 oz) of lubricant completes one cycle. Manual processes consume time, but they allow you to cover hidden areas with a spray bottle or brush.

These lubricants really stop metal from sticking to the die. They reduce friction and pop up parts smoothly. Additionally, lubricants improve the longevity of dies and protect them from wear. They often allow up to 100,000 shots before a new die is needed.

Medical Equipment Die Casting Applications

Surgical Instruments:

Manufacturers make instruments like forceps, scalpels, and retractors via die casting.  They make these tools lighter (50–200 grams), strong, and easy to sterilize. Die casting gives these parts smooth finishes, tight tolerances (±0.05 mm), and consistent quality for repeated use.

Diagnostic Imaging Equipment:

Several die-cast parts need good design to handle high temperatures up to 150°C (302°F). For example, X-ray tube housings and MRI machine components. These parts also contain excellent thermal conductivity (150-200 W/m·K) and durability in demanding circumstances.

Implantable Devices:

Manufacturers use biocompatible materials to make orthopedic screws, joint replacements, and dental implants. For instance, titanium alloys. They ensure these devices resist corrosion and have a high fatigue strength of 600 MPa. So that they last for decades inside the body.

Creation of Medical Tools via die-casting

Die-casting processes provide accurate shapes and uniformity in medical equipment. For example, surgical forceps benefit from die casting for precision. Manufacturers use stainless steel to give strength around (hardness of 40–50 HRC). They add serrated jaws to provide grip.

The box lock included in the tool offers stability. Also, the ratchet section secures tool positions. Manufacturers make shanks around 10-20 cm long for easy handling. They also include ring handles to ensure a firm grip. Die casting achieves precise shapes and uniformity for enhanced usability in medical procedures.

Material Requirements for Implantable Devices

Manufacturers commonly use titanium and aluminum alloys for implantable devices. They know material for implantable devices must meet strict standards. So titanium and aluminum provide safety and good performance in the body. Also, the implant must be reaction-proof and not harm body tissues.

The material should also not rust over time, as the body’s internal environment can be harsh. But to avoid this, you can apply extra coating, such as electroplating or anodizing the part. For example, anodizing increases wear resistance and creates smoother surfaces with a roughness of Ra ≤ 0.8 μm.

Medical Die Casting Material Properties

Comparison of TiAl Materials

Titanium and aluminum are important alloys to make high-performance medical applications. The given diagram depicts different phases based on their content and temperature.

For instance, α-Ti forms at lower temperatures (below 882 °C). It provides excellent strength but lower ductility. Similarly, when aluminum content increases to 50–55%, they form γ-TiAl. That offers good strength at high temperatures.

Ti3Al forms in the α2 region. It provides added strength and stability at temperatures like 660.45°C. Additionally, alloys that have both α2+γ phases give balanced strength and ductility. They make TiAl alloys highly suitable for high-temperature uses like medical implants.

Benefits of Die Casting for Medical Equipment

• Præcision og nøjagtighed
• Komplekse geometrier
• Economic Benefits
• Improved Patient Outcomes
• Reduced Healthcare Costs

Præcision og nøjagtighed

You can achieve unparalleled accuracy with tolerances as tight as ±0.05 mm using die casting for medial parts. This process gives exact dimensions to surgical instruments and implants. Die-casting techniques also improve the performance and fit of medical tools.

Komplekse geometrier

Diecasters can create extremely complicated designs during the die-casting process. For instance, interior features or thin-walled structures with thicknesses even below 1 mm. They can also make complex parts like X-ray tube housings and MRI components. That would be hard or costly to manufacture with other methods.

Economic Benefits

Die casting is an affordable choice for small to large production levels. Because it can reduce labor costs by up to 30% due to automation. Additionally, its rapid production cycle decreases lead times by around 2-4 weeks. This process also uses less material and minimizes its waste by less than 5%.

Improved Patient Outcomes

Die-casting techniques extend the lifespan of implant components. These techniques make them stronger. For example, if you produce orthopedic implants via die casting, then they can last 10–20 years. Because die casting reduces the need for frequent replacements. Additionally, molded parts can shorten the surgical time. They offer easy handling and require less preparation.

Reduced Healthcare Costs

The medical sector can reduce healthcare costs using die-cast parts. These parts need less repair and replacement. For example, high-quality parts with a defect rate as low as 1-2%. They also cut long-term costs for both manufacturers and healthcare providers.

Sterilization Methods for Medical Die Castings

Steam Cleaning (Autoclave):

Parts go in a special chamber. The machine heats up to around 250°F. Steam and high pressure work together to kill germs. The process takes about 30 minutes. It’s good for most metal parts. But watch out – some parts might get spots or change color.

Gamma Ray Cleaning:

This uses high-energy rays from special materials. The rays pass through packaging and kill germs deep inside parts. The process is cold and dry. Parts come out ready to use. Each part gets a set dose of rays. But the machine costs millions to build.

Gas Cleaning (Ethylene Oxide):

The parts go in a sealed room. A special gas fills the space. It kills germs by breaking them apart. The whole process takes about 24 hours. After cleaning, parts need time to air out. The gas can get into tiny holes and cracks that other methods miss.

Important Rules:

• Parts get tested after each cleaning cycle
• Workers must check the machines daily
• Every batch needs a tracking number
• Temperature and time must be recorded
• Parts must be completely dry before packaging
• Regular checks ensure the method still works well

Risk Analysis Process for Medical Devices

• Identify All Hazards: The manufacturers begin the risk analysis process for medical parts by defying all hazards. They list the risks associated with that certain device to make further improvements. For instance, electrical malfunctions, material failures, or contamination.
• Evaluate Each Hazard: They inspect the part deeply and assess how much these defects can affect the device. For instance, performance, safety, and patient health.
• Determine severity and frequency: manufacturers find the potential impact (severity) for each identified hazard. They also determine how often it could occur (frequency). If there is a high-severity hazard, it could lead to serious injury. Similarly, a low-frequency danger may not occur often yet needs monitoring.
• Assign Risk Level: After determining the severity and frequency rate in part, manufacturers set the risk levels as acceptable (low risk) or unacceptable (high risk).
• Apply Mitigation (If Unacceptable): If die casters find an unacceptable risk, then apply mitigation measures. For example, design adjustments, improvements to quality control, or better materials. They keep reassessing them until the risk becomes acceptable.
• Next Hazard: After making all changes, they repeat the process for each hazard until all risks are addressed.

Rules for Making Medical Devices

In the USA: The FDA makes sure medical devices are safe. They have rules called “21 CFR Part 820.” These rules tell companies how to make devices the right way. Companies must keep good records and test their products well.

In Europe: The EU has its own rules called MDR. These rules say what companies need to do before they can sell devices in Europe. They must prove their devices are safe and work well. They also need special marks on their products to show they follow the rules.

In Other Places: Canada has Health Canada to check medical devices. In Japan, a group called MHLW makes the rules. Each country wants to make sure devices won’t hurt people.

Konklusion:

Medicinsk udstyr Trykstøbning is a continuous process. This process involves various methods, such as hot chamber die casting and cold chamber die casting. The manufacturers make the most complicated medical parts from these techniques. Additionally, die casting offers exceptional attributes in medical devices. Its parts are strong, corrosion-resistant, and precise. These techniques are also budget-friendly and suitable for biocompatible materials like titanium.