SECTION TITLE
MATERIALS • PROCESSES • FINISHES
Chemical etching is a technology to process all metals
produced – they can lead to entanglement with the cutting tool, making automated machining challenging. Te use of chemical etching overcomes many of these issues, but even etching titanium is difficult, as the metal forms a protective oxidised coating when exposed to air, meaning it cannot be etched with standard etch chemistries. To overcome this, Precision Micro developed a process, investing in specialist equipment and process chemistry, to produce etched parts comparable to this produced in stainless steel. Precision Micro is one of the few companies that can photo-etch titanium on a production scale, today supplying a number of biocompatible medical devices to industry-leading OEMS such as cranial and dental implants which benefit from complex openings with depth-etched countersink features.
How do you etch aluminium? Aluminium exhibits many of the attributes of titanium – notably its high strength to weight ratio and natural corrosion resistance – but whereas titanium is stronger and more corrosion resistant than aluminium,
56
www.engineerlive.com
aluminium has a better fatigue limit, which makes it ideally suited to aerospace applications where fatigue limits must be high.
When conventionally machining aluminium, there are a number of problems, the biggest being what is termed “the built- up edge” – basically the welding of work- piece material to the tool edge, and the subsequent loss of effective geometry that causes increases in cutting forces and quality problems such as scratches in the surface and cloudy finish. For many suppliers, aluminium is also difficult to photo-etch effectively as the heat energy it releases during etching often results in a rough, granular edge.
As with titanium, Precision Micro has
developed a method for etching aluminium and its alloys, producing edge profiles comparable with those etched in a much easier to process metal, namely stainless steel. As an AS 9100 accredited supplier,
Precision Micro etched components for a wide range of aerospace applications, including light-weight helicopter air intake grilles and heat transfer plates used in aircraft dehumidifiers and engines, the latter
often requiring multiple designs which can be set-up cost-effectively.
How do you etch steel and stainless steel?
Although the likes of stainless steel, copper, and nickel are less troublesome to photo-etch, they still require the application of experience and considerable investment in processing technologies to optimise customer outcomes. Due to its versatility, stainless steel is used in a wide variety of applications in numerous industry sectors, and is a preferred metal in many instances due to its corrosion resistance properties and for the different versatile grades that are available. Precision Micro photo etches a wide range of austenitic (300) and martensitic (400) series steel grades from stock, as well as specialist grades including Sandvik Chromflex strip steels and nickel chrome, all of which amounts to the supply of 2,000,000 steel components each month. Te company specialises in a number of applications of photo etching on stainless steel, including meshes, filters and sieves (cost does not increase with design complexity) flexure springs for ABS braking systems,
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76
