Pyrotechnic Bolt & Rod Cutters

Bolt Cutter and Target

 

The Pyrotechnic Bolt Cutter  (or Rod Cutter) consists of an initiator, a chisel shaped cutter blade, a blade positioning shear pin and an anvil in a cylindrical housing. The bolt to be cut fits through a clearance hole in the housing, placing it against the anvil. When the initiator functions, the blade is accelerated and impacts the bolt, forcing it to cut through against the anvil. This cutting process completely fractures the high strength steel bolt or rod.

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How A Pyrotechnic Bolt or Rod Cutter Works

Pyrotechnic bolt and rod cutters are used for cutting high-strength bolts and metal rods. In this approach, the front end of a piston is made into a shape of a cutter blade and gains impulse by the drive from the gas combustion to cut both metallic and nonmetallic materials. When used as a separating device, the cutter mainly functions by cutting the connecting bolts, providing an alternative to unlocking bolts. Pyrotechnic cutters are advantageous for the following reasons: (1) they allow the separation structures to be connected by ordinary bolts, not requiring weakening treatment; (2) their bearing capacity is high; (3) they achieve unlocking by cutting the bolt from the middle; (4) their performance is not affected by the installation conditions, such as the bolt pre-load force; and (5) after the cutting work is completed, the gas is completely sealed in the chamber, and no undesired products are generated. The key factors for the cutter are the design of the cutter blade and the control of the cutting capacity to ensure that the bolts can be completely cut.

Applications

We have designed and manufactured 100’s of different cutters for 100’s of applications. Qualified and used in various military, commercial, and aerospace platforms including spacecraft, launch vehicles, aircraft (military and commercial), satellites and multiple missile platforms.

Functions

Pyrotechnic bolt and rod cutters are used to sever steel bolts or rods on a multitude of applications. Typical applications for pyro cutters are stage separation systems,releasing pre-loaded / folded assemblies ( i.e. wing, fin, etc.) and releasing cargo or munitions, and flight termination systems (FTS).

Performance

  • Operating Temperature
    -54°C to +71°C (-65.2°F to 159.8°F)
  • Function Time
    With the application of the All-Fire current, the cutter will completely sever the target in < 20 milliseconds
  • Reliability
    99% at 95% confidence level
  • Altitude
    10,000 feet underwater to Deep Space
  • Estimated Weight
    27 to 173 grams
  • Target Materials
    High strength steel bolts and rods up to ½ inch diameter
  • Applicable Specifications
    MIL-DTL-23659
    MIL- STD-1512
    MIL-STD-1576
    MIL-HDBK-83578
  • Electrical
    Bridgewire Resistance 0.9 to 1.30 ohms
    Insulation Resistance 100 megohms 500 VDC
    No Fire 1 amp/ 1 Watt for 5 Minutes
    Recommended All Fire 4.0 Amps for 50 millisecond duration
    ESD 25KV Electrostatic discharge: 25 kV DC from 500 pF Cap thru a 5k ohm resistor – shorted pins to case and pin-to-pin
    Electrical connections can be lead wire, bayonet or threaded connectors

Envelope/Interface Design

Energetic loading, blade geometry, anvil geometry, and structural materials are all variable based on target and application requirements. Each blade is optimized for the intended target material to ensure precision severance.

Cutter Envelope Technical

Questions to Consider

  • Application – what are you trying to accomplish?
  • What are your target materials?
  • What are your space constraints?
  • Is containment required?
  • Redundancy requirements?
  • Input power requirements – electrical, ETL, mechanical?
  • Environmental requirements?
  • Qualification requirements?
  • Military or other requirements?