Environmental Test Fixtures
Design and Evaluation
Let Crossfire Engineering, Inc. (CEI) take the “Rock ‘n’ Roll" out of your test and give you a great Shake. Call CEI for more than a fair shake from your shock or vibration fixture. CEI was established in February of 1981 (Crossfire Engineering), as an engineering company specializing in the design and manufacturing of vibration and shock fixtures for several aerospace and military environmental test communities. We incorporated in the State of Connecticut in 1984 as Crossfire Engineering, Inc.
CEI no longer produces the physical fixtures but continues to provide complex fixture drawings, interface with pattern makers and magnesium casting companies to provide our customers with a fixture they can control from patern to finished machining. We use our expertise to provide pattern, casting and machining drawings via the internet so you can manufacture a fixture to best meet your test and evaluation specifications at a far reduced cost.
CEI also provide engineering test personal to test and certify your facility or aid in the design of your environmental test systems. The design department at CEI has over a forty years of experience in the environmental testing and design field. Our designers hold many U.S. Patents for several new and innovative testing methods and hardware; the methods and hardware are in wide usage throughout the U.S., Asia and Europe.
CEI's environmental testing hardware and certification testing is divided into two categories:
- 1st. - Our standard and custom design shock and vibration fixtures are designed for customer manufacturing in cast magnesium: AZ91E-T4 and K1A-As Cast depending on Weight, Stiffness, Damping Capacity and Dimensional Stability requirements. Other alloys of various hardness are available as needed. Our typical fixtures consists of Head (or Armature) Plates and Slip Plates, Head Expanders, Cubes, Vertical and Custom Fixtures Vibration Fixtures.
 . Figure 104 on the right shows the precision machined and hardened steel bearing washers which we press into all mounting bolt holes in order to provide a hard seat to allow the full vibration machine’s mounting torque to be applied without a bearing failure in magnesium fixture. All our washers are countersunk to prevent the mounting bolts from bearing on their head-shank fillet radius.
- 2nd. - CEI supplies consulting support to environmental test facilities to aid their certification to all industrial and military specifications to optimize the union between your test piece(s) and your environmental test equipment.
Return to Top of page
 CEI provides designs for all head plates to interface test articles directly to the shaker table armature. All head plate designs incorporate the specific hole pattern for your shaker head. Accelerator mountings can be provided in the event that the head plate will be mounted to a slip table for vibration in the horizontal plane. Our head plates are normally supplied in 1.5 to 3 inches in thickness but thicker head plates are available on request.
Return to Top of page
 CEI designs a wide selection of webbed and solid head expanders to mount test articles which are larger than the shakers armature head. While solid cast fixtures provide the most conservative fixture design by elimination of non uniform surfaces web cast fixtures are often required due to weight limitations.
Return to Top of page
  CEI designs cube fixtures to allow for multiple vibration plains for several components at one time. Figure 088 on left has been used to test small ICs to failure. Cube rotation on Fig. 088 is by use of one large holding stud. The bigger cube at the right was used for mounting industrial components for 3 axis testing without cube rotation and requires customer to move components to the three planes of vibration. Fig. 047 can hole four large parts at one time.
Return to Top of page
 Vertical Fixtures allow the test pieces to be mounted in other that a horizontal plane. Much like a Cube but only holding test pieces on one surface. These are most useful in mounting heavy pieces while maintaining cg alignment.
Return to Top of page
  This type of fixture is designed to optimize the interface of test piece to shaker table armature for the vibration specification required. This type of design insures:
- 1. The highest possible natural fixture frequency with the test piece mounted
- 2. Alignment of the center of gravity of the test piece with the shaker armature.
- 3. Absolute simplest mounting for an shape test piece without compromising response and weight.
- 4. Use of cast magnesium in most custom applications insures the use of highest dampening magnesium alloys to provide minimum weight for maximum shaker life.
Return to Top of page
|
