Starting in 2023, we have delivered the first over-molded temperature sensor (probe) with IP 68 protection. In this blog post, we are introducing an over molded probe with NTC 10k thermoelement filled with thermoplastic rubber.
Our standard cable temperature sensors, that are not over-molded, have IP65 protection regardless of the cable type: PCV (up to 105 °C), Silicone (up to 180 °C), High-Temperature Silicone (up to 250 °C) or Fiberglass (up to 400 °C).
But since the summer of 2023 our production capacity has extended to the manufacturing of over-molded cable temperature sensors that are IP68 resistant.
What does IP68 mean?
The abbreviation IP stands for “International Protection” but in sometimes it is also intepretedas “Ingress Protection” or shortly the “IP rating”. The IP ingress protection types provide a system that describes how the housing of electrical equipment is protected against the ingress of particles / dust and water.
In our case of IP68:
- The first digit, the number “6”, means that the instrument has total dust ingress protection.
- The second digit, the number “8”, means that the instrument is suitable for permanent submersion in water.
However, the standard does not specify the maximum submersion depth – because the pressure can be very different at different depths.
As the IP68 rating must always be better than the IP67 rating, that means that the instrument may be submersed for at least 1 m.
Technical specifications, features and tests requested for the over molded NTC10K probe with IP86 protection
Our client requested the following technical specifications for the over-molded sensor:
- Type: Probe NTC Over molded with cable-double insulation IP68 – 2 Wire
- Element: NTC 10k (1% Beta)
- Case:
- Material: thermoplastic rubber
- Length: 20mm
- Diameter: ⌀ 5mm
- Cable:
- Material: Thermoplastic rubber (est) poly (int),
- Color – Cable: Black
- Color – Cable Leads: Black and White
- Dimensions Section: 2 × 0,25mm2 , ⌀ 3,3mm (diameter)
- Probe length: 2,5 meter
- Connector cable: None
- Terminals: Pins
- Filling: Thermoplastic rubber
- IP protection grade: IP 68
Requested Technical features for custom NTC probe – overmolded:
- Operating range: from – 50°C to +110 °C,
- Tolerance: 1%
- Protection grade: IP 68
- Response Time: K=10’’ in liq. V= 2m/s
Requested Tests for custom NTC probe – overmolded:
- Traction Cable-Case: kg 2/24 h
- Ohmic Check: 25°C 10 Kohm
- Insulation degree: 20 Mohm 500 Vcc
Technical Drawing – over-molded cable probe sketch
Below you can see a basic sketch we did for the client based on the above specifications.
Test Samples of over-molded temperature sensor before manufacturing
We have created several test samples of the probe for internal and client testing. We performed stress tests and integration testing before we started the real manufacturing process of 250.000 pieces.
What is overmolding?
Over-molding refers to a process used to combine at least two often dissimilar materials into one part – in order to create one object or design. Of the two or sometimes more materials, one material is commonly known as the substrate. It is either partially or fully covered by a second material or materials referred to as the over-molded material. The substrate material can be just about anything: metal, plastic, or glass. The over-molded material is often a rubber or thermoplastic material. The over-molding process often results in either a chemically bonded part or the materials being mechanically interlocked.
Over molding offers several benefits one in particular is that it can eliminate secondary operations when building parts thereby reducing manufacturing costs. Over molding can also deliver a special feel to the product – e.g. softening edges or a more pleasant overall product feel.