Cartridge heaters are compact, powerful and highly efficient heating elements used in many industrial applications. They are designed to transfer heat directly into metal blocks, molds, tools, dies and mechanical assemblies where stable and controlled heating is required.
At Caldor Heat, we manufacture custom cartridge heaters in different diameters and lengths, depending on the technical requirements of each application. Choosing the correct diameter is not only a question of available space. It directly affects heat transfer, power capacity, durability and installation quality.
Why cartridge heater diameter matters
The diameter of a cartridge heater defines where it can be installed and how much heat it can safely deliver. A small cartridge heater is suitable for compact cavities and test fixtures, while larger diameters are preferred for heavy industrial blocks, presses and special heating assemblies.
If the heater is too small for the application, heating may be slow or insufficient. If the heater is too powerful or installed with poor thermal contact, it may overheat and fail earlier than expected. For this reason, each cartridge heater must be selected according to bore size, heated mass, working temperature, power requirement and operating conditions.
Cartridge heater size range manufactured by Caldor Heat
Caldor Heat produces cartridge heaters from Ø6 mm up to Ø40 mm, with lengths from 30 mm up to 4500 mm, depending on the diameter and application.
| Diameter | Minimum Length | Maximum Length | Typical Use |
|---|---|---|---|
| Ø6 – Ø8 mm | 30 mm | 600 mm | Small cavities, compact blocks, test fixtures |
| Ø10 – Ø12.5 mm | 35 mm | 1500 mm | Molds, hot runners, packaging machinery |
| Ø16 – Ø20 mm | 45 mm | 3000 mm | Large heated blocks, presses, production lines |
| Ø25 – Ø40 mm | 80 mm | 4500 mm | Large industrial blocks and special heating assemblies |
This range allows us to supply both small precision heaters and long industrial cartridge heaters for demanding production environments.
Ø6 – Ø8 mm cartridge heaters
Cartridge heaters with diameters between Ø6 mm and Ø8 mm are mainly used in applications where space is limited. They are suitable for small cavities, compact metal blocks, laboratory equipment, test fixtures and precision heating areas.
These heaters can be manufactured from 30 mm up to 600 mm in length. Because the diameter is small, correct power calculation and good bore contact are especially important. A small heater working in a poorly machined hole may overheat quickly if heat is not transferred properly to the surrounding metal.
Ø10 – Ø12.5 mm cartridge heaters
The Ø10 mm to Ø12.5 mm range is one of the most common choices for molds, hot runner systems and packaging machinery. These heaters provide a good balance between compact size and heating capacity.
Caldor Heat can manufacture this range from 35 mm up to 1500 mm in length. They are frequently used in plastic injection molds, sealing systems, forming tools and machine parts where reliable and repeatable heating is required.
For mold and hot runner applications, temperature control is essential. Depending on the project, the heater can be supplied with suitable cable insulation, mechanical protection or integrated sensor options.
Ø16 – Ø20 mm cartridge heaters
Cartridge heaters between Ø16 mm and Ø20 mm are used for larger heated blocks, presses and production lines. These diameters allow higher heating capacity and better suitability for heavier metal masses.
They can be produced from 45 mm up to 3000 mm in length. This makes them suitable for applications where heat must be distributed over a longer section of the part or where the heated component has a larger thermal mass.
Typical applications include industrial presses, heated plates, aluminum or steel blocks, sealing systems, forming equipment and continuous production machinery.
Ø25 – Ø40 mm cartridge heaters
For large industrial blocks and special heating assemblies, Caldor Heat manufactures cartridge heaters from Ø25 mm up to Ø40 mm. These heaters are designed for demanding applications where high thermal capacity and long heated lengths are required.
This range can be produced from 80 mm up to 4500 mm in length. Large cartridge heaters are commonly used in special machinery, heavy industrial tools, large heated blocks and custom heating systems.
For these applications, technical analysis is especially important. Power, active length, cable exit, material, insulation, temperature control and installation tolerances must all be checked before production.
Correct installation is critical
A cartridge heater can only work properly when it is installed correctly. The bore must be clean, accurately machined and suitable for the heater diameter. Excessive clearance reduces heat transfer and may cause the heater to overheat.
For best performance:
- the hole should be clean and free from oil, dust, chips or deposits;
- the heater should be inserted along its full active length;
- the heater should not be forced with hammer blows;
- the cable should not touch hot surfaces;
- temperature must be controlled with a suitable sensor and controller;
- the heater should not be operated without proper thermal contact.
Good installation improves heating performance, reduces energy loss and extends service life.
Custom production for industrial applications
Every industrial heating application has different requirements. Diameter and length are only the starting point. For correct production, the following details are usually required:
- diameter;
- total length;
- active heating length;
- voltage;
- power;
- working temperature;
- cable length;
- cable type;
- cable exit position;
- quantity;
- application details;
- drawing or photo of the old heater.
If the customer does not have a complete technical drawing, Caldor Heat can also work from samples, photos and basic measurements.
Caldor Heat cartridge heaters
Caldor Heat manufactures cartridge heaters for molds, hot runners, packaging machinery, presses, production lines, heated blocks and special industrial assemblies.
With available diameters from Ø6 mm to Ø40 mm and lengths from 30 mm to 4500 mm, we can supply both compact precision heaters and large industrial cartridge heaters designed for demanding operating conditions.
For a quotation, send us the heater diameter, length, voltage, power, cable details, quantity and application information. Our team will check the technical requirements and recommend the correct cartridge heater construction for your project.
Caldor Heat – custom electric heating solutions for industrial applications.