Transducers

Features

• Minimised distortion and low heat input allowed welding to be a final assembly operation
• Many dissimilar materials can be joined
• Thick to thin parts can be easily welded
• Beam throw can reach otherwise inaccessible parts
• Minimum heat affected zone obviates the need for subsequent heat treating
  and yields very reproducible deflection characteristics on thin diaphragms
• Reject rate is minimised or even eradicated all together because of very reproducible weld parameters

Problem

Manufacturers in the petrochemical, aerospace, food and drink processing industries and in hundreds of other fields where physical parameters are monitored could not find a really satisfactory method for assembling small transducers containing electronic components. There was no technique available that combined sufficiently high integrity welds with the low distortion necessary in this application.

Solution

Welding with electron beam techniques enabled significant improvement in performance and miniaturisation of all types of transducer. For many years the high capital cost of beam welders prohibited widespread use of this method, but the development of electron beam welding as a production tool, combined with the resultant lowering of relative costs has allowed the process to be used much more extensively. Many manufacturers found the technique so successful, using equipment specially adapted for their products, that they are now installing their fourth or fifth CVE machine.

Many users of early machines have availed themselves of modern developments in electron beam welders, especially in the area of control equipment, commissioning CVE to carry out extensive upgrades and refurbishment of aged machines.

Process

CVE has experience in welding transducers in a wide range of materials, with wall thicknesses ranging from 0.02mm to 15mm, including:

• Inconel
• Stainless steel
• Monel
• Hastalloy
• Beryllium copper
• Nispan
• Maraging steels

A typical welding parameter would involve an approximate heat input of 140 watts at a welding speed in excess of 1500 mm/min. With such parameters and suitable jigging, distortion and damage are eliminated and high quality, leak-tight welds are achieved.

The high pumping speeds associated with CVE welders reduce floor-to-floor time and even with amortisation and labour costs included, welding cost per part is attractively low.

Many transducers contain up to ten or twelve welds, the welding process being part of the assembly operation. Another advantage of electron beam welding is the easy attachment of sealing or deflecting diaphragms to the body of the transducer.

Electron beam welding contributed to the development of transducer technology and fabrication to widen the scope and performance of these devices, for example; miniaturisation, higher operational temperatures and greater accuracy.