Split Sheath Miniature Cartridge Heaters with Hot Tip
NPH Split Sheath Mini Cartridge Heaters with Unique Hot Tip Profile 
Unique Hot Tip-Miniature 3mm and 4mm Split Sheath Cartridge Heaters-W Precision Heating for Small Diameter Industrial Applications
Split sheath miniature cartridge heaters with hot tip design are engineered for precision heating applications where conventional cartridge heaters cannot fit. Commonly manufactured in 1/8" (3 mm) and 4 mm diameters, these compact heaters provide rapid heat transfer, excellent temperature uniformity and long service life in demanding industrial environments.
Unlike conventional cartridge heaters, split sheath miniature heaters expand slightly during operation to improve contact with the bore wall. This enhanced thermal contact increases heat transfer efficiency while lowering internal element temperatures, helping reduce heater stress and extend operating life.
True hot tip construction allows heat to be delivered directly to the bottom of the bore, eliminating the cold tip section commonly found in standard cartridge heaters. This design improves temperature consistency and thermal response in deep bore and precision tooling applications.
Split sheath miniature cartridge heaters are widely used in hot runner systems, injection molding nozzles, medical equipment, semiconductor manufacturing, packaging machinery, laboratory instrumentation and precision thermal systems requiring concentrated heat in extremely small spaces.
Heater Construction and Features
These heaters are manufactured using a continuous nickel-chromium resistance wire embedded in high purity magnesium oxide (MgO) insulation inside a stainless steel or Incoloy sheath. The compacted MgO provides excellent dielectric strength and efficient heat transfer.
Available options may include:
- Hot tip fully heated construction
- Precision ground diameters
- Custom heated lengths
- Variable watt density designs
- Internal Type J or Type K thermocouples
- Pt100 RTD sensors
- Moisture resistant seals
- Stainless steel braid or armor cable protection
- Straight or right-angle lead exits
Common lead insulation options include PTFE (Teflon), kapton, fiberglass and high temperature mica-glass insulation.
Typical heater sizes include:
- Diameters: 1/8" (3 mm) and 4 mm
- Lengths: 1/2" to 6"
Custom voltages, wattages and configurations are available for OEM and specialized industrial applications.
Common applications include:
- Injection molding hot runner systems
- Nozzle and sprue heating
- Heat sealing equipment
- Packaging machinery
- Laminating systems
- Medical probes and diagnostic equipment
- Laboratory heating systems
- Semiconductor process equipment
- Thermal test fixtures
- Sensor calibration systems
- Small molds and precision dies
- Heated platens and tooling fixtures
Industries commonly using split sheath miniature cartridge heaters include:
- Plastics processing
- Medical device manufacturing
- Aerospace and defense
- Semiconductor manufacturing
- Electronics manufacturing
- Laboratory and scientific equipment
- Packaging and converting
- OEM machinery manufacturing
- Automotive component manufacturing
- Industrial automation systems
Depending on watt density, fit tolerance and sheath material, split sheath miniature cartridge heaters can typically operate at temperatures up to approximately 1200°F (650°C).
Why Choose NPH Split Sheath Miniature Cartridge Heaters
National Plastic Heater split sheath miniature cartridge heaters are engineered for precision, durability and consistent thermal performance in compact industrial heating applications.
Key advantages include:
- Superior bore contact through split sheath expansion
- True hot tip heating capability
- High watt density performance
- Compact diameters for limited space applications
- Improved heat transfer efficiency
- Long service life
- Custom engineering support
- Precision manufacturing tolerances
These heaters provide reliable and efficient heating for demanding applications requiring precise localized temperature control.
Technical Resources & Engineering Downloads
3mm OD x 0.5 in. long-Miniature-Micro Split Sheath Cartridge Heater, 12V, 24V, 120v, Max. Watts, 8 in. Red Teflon Leads - Copy - Copy
3mm OD x 0.5″ long-Miniature-Micro Split Sheath Cartridge Heater, 12V, 24V, 120v, Max. Watts, 8″ FG Leads
3mm OD x 0.75 in. long-Miniature-Micro Split Sheath Cartridge Heater, 12V, 24V, 120v, Max. Watts, 8 in. Red Teflon Leads - Copy - Copy
3mm OD x 0.75″ long-Miniature-Micro Split Sheath Cartridge Heater, 12V, 24V, 120v, Max. Watts, 8″ FG Leads
3mm OD x 01″ long-Miniature-Micro Split Sheath Cartridge Heater, 12V, 24V, 120v, Max. Watts, 8″ FG Leads
3mm OD x 1 in. long-Miniature-Micro Split Sheath Cartridge Heater, 12V, 24V, 120v, Max. Watts, 8 in. Red Teflon Leads - Copy
4mm OD x 0.5 in. long-Miniature-Micro Split Sheath Cartridge Heater, 12V, 24V, 120v, Max. Watts, 8 in. Red Teflon Leads
4mm OD x 0.5″ long-Miniature-Micro-Split Sheath Cartridge Heater, 12V, 24V, 48V, 120V- Max. Watts, 8″ FG Leads
4mm OD x 0.75 in. long-Miniature-Micro Split Sheath Cartridge Heater, 12V, 24V, 120v, Max. Watts, 8 in. Red Teflon Leads
4mm OD x 0.75″ long-Miniature-Micro Split Sheath Cartridge Heater, 12V, 24V, 120v, Max. Watts, 8″ FG Leads
4mm OD x 1 in. long-Miniature-Micro Split Sheath Cartridge Heater, 12V, 24V, 120v, Max. Watts, 8 in. Red Teflon Leads
4mm OD x 1″ long-Miniature-Micro Split Sheath Cartridge Heater, 12V, 24V, 120v, Max. Watts, 8″ FG Leads
Miniature Cartridge Heaters-Lead Material Types-Black PVC
Mini Cartridge Heater with Sil. Rubber Lead
Hot Tip Split Sheath Miniature & Small Diameter Cartridge Heaters-FAQs
NPH miniature split sheath cartridge heaters are designed for applications requiring highly concentrated heat in extremely limited spaces. Available in 1/8", 2mm, 3mm, 4mm and other small diameters, these hot tip cartridge heaters provide excellent heat transfer, easy removal, long service life and uniform temperature distribution. The following frequently asked questions address heater sizing, watt density, lead configurations, thermocouple options, applications, operating temperatures and custom manufacturing capabilities.
What are miniature split sheath cartridge heaters?
What are miniature split sheath cartridge heaters?
Miniature split sheath cartridge heaters are small diameter insertion heaters designed for precision heating applications where space is limited. Their patented split-sheath construction expands when energized to improve heat transfer and contracts when de-energized to simplify removal.
What is the advantage of a split sheath cartridge heater?
Split sheath cartridge heaters expand against the bore wall during operation, creating improved thermal contact and more efficient heat transfer. This design helps reduce operating temperatures, improve heater life, and simplify heater removal during maintenance.
What is a hot tip cartridge heater?
A hot tip cartridge heater provides heat all the way to the end of the heater, eliminating the cold tip commonly found in conventional cartridge heaters. This allows more uniform temperature distribution and improved heating performance in compact applications.
What miniature cartridge heater diameters are available?
NPH designs miniature cartridge heaters in common sizes including 1/8" (3.175 mm), 2 mm, 3 mm, 4 mm, and other small diameters. Custom diameters and lengths may also be available depending on application requirements.
What industries commonly use miniature cartridge heaters?
Miniature cartridge heaters are widely used in medical devices, laboratory equipment, semiconductor manufacturing, analytical instruments, packaging machinery, plastics processing equipment, aerospace systems, electronics manufacturing and OEM process heating applications.
Can miniature cartridge heaters be supplied with built-in thermocouples?
Yes. NPH can design miniature cartridge heaters with internal Type J or Type K thermocouples for improved temperature monitoring and precise process control.
What voltages are available for miniature cartridge heaters?
Miniature cartridge heaters can be manufactured in various voltages including 12V, 24V, 48V, 120V, 240V and other custom voltages depending on heater size, wattage and application requirements.
What lead wire and termination options are available?
NPH offers a variety of lead exits and terminations including fiberglass insulated leads, PTFE leads, stainless steel braid, armor cable, right-angle exits, swaged leads and custom configurations to suit installation requirements.
How do I determine the proper wattage for a miniature cartridge heater?
Proper heater selection depends on material type, operating temperature, available voltage, warm-up time, hole fit, heat losses and application conditions. NPH can assist with preliminary heat calculations and heater recommendations.
What is the maximum operating temperature of a miniature cartridge heater?
Maximum operating temperatures vary depending on sheath material, watt density, installation conditions and heat transfer efficiency. Properly designed miniature cartridge heaters can operate at elevated temperatures while maintaining long service life.
Can NPH manufacture custom miniature cartridge heaters?
NPH designs engineers and supplies custom miniature cartridge heaters with special diameters, heated lengths, cold sections, thermocouples, lead exits, sheath materials, voltages and wattage ratings to suit specific OEM and industrial applications.
Why choose a miniature split sheath cartridge heater instead of a conventional cartridge heater?
Split sheath miniature cartridge heaters provide superior heat transfer, more uniform temperature profiles, improved heater removal, reduced maintenance costs and longer service life compared to many conventional miniature cartridge heater designs
How To Order Cartridge Heaters
We Ship Our Kapton & Process Heaters To OEM’s & Industry World Wide