whitepaper chemical etching in a world of precision engineering innovators in chemical etching since 1970 introduction The trend in many industries is Chemical Etching in Micro Manufacturing This whitepaper on Chemical Etching aims to give you a good towards smaller, more complex understanding of the technology and its applications. It covers an Chemical Etching is a high precision subtractive and more delicate devices with manufacturing process that uses baths of introduction of the technology, explanation of detailed process, higher levels of performance. temperature- regulated etching chemicals to technical capabilities, comparison with other micro manufacturing Miniaturisation is no longer a wish; selectively remove material to produce high precision processes, markets served and applications, etc. it is a fact and we see across all metal parts in any desired shape. kind of industries. Compared to other micro manufacturing techniques, such as Stamping, EDM, CNC, Laser Cutting, and There are many advantages to making smaller Water Jetting, Chemical Etching is more cost efficient products, but you have to be aware of the challenges with shorter lead time, more design flexibility, and no that this implies. Designing smaller parts doesn’t mean need for deburring. It is an optimal choice for precision you can lower product performance expectations. metal part manufacturing, regardless of prototyping or Quite the contrary: the basic materials used to industrial production. transform designs into actual products must perform better than ever before, since the smallest irregularity will have a much larger effect on the end result. Micro manufacturing is becoming a big challenge for many industries. Metal parts need to get smaller by the day, yet stay ultra-precise, at a reasonable cost. 2 Tecan chemical etching whitepaper 3 chemical etching subtractive manufacturing Etchable Materials Almost any metal can be etched. These include (but are not limited to): • Stainless Steels: Wide Range of Austenitic, Ferritic and Martensitic Stainless Steels; • Mild Steel, Carbon Steel, Tool Steel, Spring Steel; What is Chemical Etching? • Aluminum: Including Aircraft/Aerospace grades; • Molybdenum; Chemical Etching is a subtractive manufacturing process that use baths of temperature-regulated etching • Nickel Alloys: Inconel, Mu-Metal, Alloy 42 (Nilo 42), Invar; chemicals to selectively remove material to produce high precision metal parts in any desired shape. • Copper: Including C110 and C101 (Oxygen Free); It is also referred to as Chemical Milling, Photo (Chemical) Etching, Electrochemical Etching, Photo (Chemical) • Brass, Phosphor Bronze, Beryllium Copper, Nickel Silver; Milling, Photo Chemical Machining, and Industrial Etching. The process is ideally suited to a wide range of • Many other materials – please call us to discuss your needs. materials. Most commonly used materials include stainless steel, non-, low-alloy steel, nickel, copper, bronze, brass, etc. Many other types of metal, e.g. gold, silver, aluminum, hastelloy, titanium, and special alloys such as You are always suggested to talk to one of our industry leading experts if you are considering any nitinol and vitrovac, can be etched under appropriate conditions. specific material that’s not listed above. Chemical Etching process Profile Geometries of Chemical Etching Chemical Etching process can be concluded in a series of steps including Cleaning, Laminating, Exposing, Single sided etching Specific depth, profile, or pattern can easily be achieved with Single Developing, Etching, and Stripping, after which rigorous inspection is automatically carried out on all Sided Etching. components. Photo sensitive coating UV light Double sided etching Double-sided Etching is used for engraving on both sides, which allows for extra design flexibility. Ratio etching With Ratio Etching, products can be etched to a 50/50, 60/40, 70/30, Metal or 80/20 ratios if necessary. Conical apertures or cutting edges can also be achieved. 1 - Cleaning 2 - Laminating 3 - Exposing Material is cleaned The cleaned metal ‘blank’ The metal sheet is then to remove all surface is then coated with a exposed to ultra-violet 2/3 Etching 2/3 Stage Etching can be used to achieve multiple depths, requiring contamination. This light-sensitive photoresist light, which hardens the additional imaging. provides a suitable surface in a clean room. photoresist. for resist adhesion later in . the process. Parallel profile etching Also referred to as “Seagull Profile”, Parallel Profile Etching is a typical etching profile used in particular to reduce etch cusp Etchant spray Photo-resist removed Photo-resist lacquer Convex profile etching For through-etched components Convex Prole Etching, also referred to as Under Etching Profile, is a typical industry standard edge condition. Concave Profile With Concave Profile Etching, also referred to as Over Etching Profile, a straighter edge profile can be achieved. 4- Developing 5 - Etching 6 - Stripping Unexposed areas are Etching chemistry is The resist is removed in developed away, leaving sprayed on both sides of the end to leave behind behind the bare metal. the metal at high pressure. burr- and stress-free This accurately removes components. the unwanted metal. 4 Tecan chemical etching whitepaper 5 Dimensions of Holes/Features Key Benefits of Chemical Etching: • Burr- and stress- free; Pitch • Eliminates cold working (common use in stamping and punching) or heat affected zones or recast layers for laser and wired EDM; • Low tooling cost; Hole Diameter • Design flexibility; • Fast turnaround; • Etched fold lines for ease of forming without tools; • Magnetic and other material properties unaffected; • Complex designs are easy to tool; • From prototype to industrial manufacturing volume; • Company logos, part numbers, and QR codes of all kinds can easily be etched into the surface during Corner Bar Slot Material manufacture. radius Width Width Thickness Chemically Etched Products: Material Minimum hole Minimum Minimum Minimum thickness (T) µm Ø µm radius µm bar size µm tolerance ±µm 25 > 75 38 25 15 50 > 90 45 40 25 75 > 110 55 60 25 100 > 140 70 80 25 150 > 210 105 120 25 200 > 240 120 160 30 250 > 300 150 200 38 300 > 360 180 240 45 400 > 460 230 320 60 500 > 560 280 400 75 If a job is beyond the specification limits set out in this document then special advice and approval must be sought from the Veco’s Application Engineering team. All the above parameters are subject to the following: • Component size; • Material type & grade; • Distribution of features; • Component quantity. 6 Tecan chemical etching whitepaper 7 chemical etching vs. micro stamping Stamping, also known as pressing, is a manufacturing process that place flat sheet metal into a stamping press, where a tool and die surface forms the metal into the desired shape. The trend of miniaturisation has driven the industry to the micro level, which is referred to as Micro Stamping. Cost Efficiency Design Flexibility Unlike Chemical Etching which features no Chemical Etching allows for more design tooling cost, Stamping always requires flexibility due to the fact that it requires no substantial investment in tooling and tooling investment and that it has a very short installation: both monetary-wise and time- lead time, while with Stamping modifying a wise. One stamping die can easily cost design means making a completely new die thousands of dollars, not to mention the extra and investing on tooling and setting up all over costs for setting up and maintenance costs again. This also means that Chemical Etching chemical etching in micro over time. is perfect for small amount prototyping as well as industrial production. Lead Time manufacturing With Stamping, the lead time can be 6-8 Quality/Accuracy weeks only for preparing the tooling. Even Chemical Etching is a high precision micro- after the stamping tool is completed, extra manufacturing technology. With etching, a time (and costs) will incur for setting up the higher level of accuracy and precision can be tooling in the stamping press. With Chemical achieved. Moreover, etched parts are Etching, lead time is a matter of days. completely burr- and stress-free while Compared to those who still stamp their stamped parts feature partial burrs and stress precision metal components, you can receive at cutting edge. Although minor burr or stress your ultra-precision etched parts even before can be acceptable for some applications, their stamping tool is ready! it might be a stumbling block for your next breakthrough. Compared to Stamping, or Micro Stamping, Chemical Etching is clearly the more effective process no matter for prototyping or industrial production with shorter lead time, lower costs, better quality, and more design flexibility. 9 chemical etching vs. laser cutting chemical etching vs. electro discharge machining Laser Cutting is another subtractive manufacturing process. It works by directing the output of a high-power laser most commonly through optics to cut materials in order to achieve the desired products. Electrical Discharge Machining (EDM), also known as spark machining, burning, die sinking, wire burning, or wire erosion, is a manufacturing process whereby a desired shape is obtained by removing materials with Cost Efficiency Design Complexity electrical discharges (sparks). When it’s a small volume production or Chemical Etching and Laser Cutting are both prototyping, Laser Cutting can be more cost- flexible regarding design. When the design is effective