Micro metal fabrication with the use of photo chemical etching technology

1. 18 distribution & supply chain management
Precision photo
chemical machining
Production of metal parts with
NO hard tooling or press required By Hassan Nojoumi, president,
Shimifrez Inc., Concord ON
There’s an alternative monitored. Dimensional tolerances are a Three-dimensional masking process for the selective removal
method to produce pre- function of the thickness of the mate- of material. As this method is based on
cision parts today – rial. Typically, dimensions can be held to products a chemical reaction, undercuts or over-
PCM – Photo Chemical ±10% of the thickness of the material. Hand-foldable, etched bend channels cuts can be generated depending on the
Machining also known are one of the unique features that density of the chemical material and the
as chemical blanking. Complexity made simple Shimifrez can incorporate into a RFI/EMI duration of etching.
With the fastest response time and low- shielding enclosure (board level shield-
est photo tooling costs available, PCM PCM can produce complex parts that ing). Etched bend channels allows users
is suitable for both prototyping and would be either impossible or impractical Electroforming
to bend the sidewalls of a shield from
manufacturing medium / large produc- to produce by stamping or laser cutting. a 2D flat part to a 3D finished shield, Electroforming is a specialized process
tion quantities of metal parts. Instead of The etching process produces parts that quickly and precisely. Bend channels can Shimifrez uses to produce precision metal
stamping or laser cutting, PCM produces are free of burrs and mechanical stress. offer the designer several benefits such as parts that are 4 to 5 times more accurate
highly accurate and identical components Investment upfront is very low since the the etched bend channels that are typi- in getting to tight tolerances than chemi-
for small and large batches. Chemical cost of photo tooling is an order or two cally intended to create 90º right angle cal etching. Electroforming is a metal
etching has no effect on magnetic prop- less than in competing technologies. forming process that grows metal through
bends. They can also be used to create
erties or deformation whether internal acute angle bends between 0º and 90º. the electroplating process. The process
stresses or thermal resulting a burr free Material properties Or since the enclosure can be formed creates an electroform piece through
component. without the need electro-deposition of a mandrel in a plat-
Virtually all aerospace, medical and
unaffected ing bath (nickel, gold or copper) onto a
for any traditional
electronics devices contain a precision Chemical etching conductive patterned surface.
forming tooling,
metal part. Shimifrez was established 30 imparts no mechanical The electroformed part can be stripped
users can typi-
years ago specifically to manufacture high stresses on metal sub- off the mandrel, once the material is
strates. Where stamping, cally save hun-
precision chemically etched components. dreds of dollars plated in the desired thickness. The elec-
PCM provides precision custom-designed punching and die-cutting troforming process allows extreme precise
impart shearing deforma- in tooling and
metal parts of any complexity and is very duplication of the mandrel. This results in
tion, and laser and water- several days of
well suited to several applications cover- perfect process control, high quality pro-
jet cutting can leave delivery lead time
ing almost every market segment includ- duction and very high repeatability. This
฀ ฀ ฀ ฀ ฀ ablative deformation, for prototype and
production needs. makes electroforming perfect suitable for
for which parts like EMI/RFI shielding, photo-chemical machin-
Finally the etched low cost production and high volumes.
sieving and metal grids, nozzle heads and ing simply dissolves the
bend channels The highly resolution of the conduc-
lead frames are required. In general this unneeded metal, leaving
exhibit a zero inside radii when formed. tive patterned substrate allows advanced
technology is particularly convenient on a flat and burr-free part.
Designers can save space on a board or geometries, tighter tolerances and higher
thicknesses between 0.01mm up to 1mm edge definition. When requirements call
(0.0005” to 0.039”), when geometries are the instrument by reducing the clear-
Materials ance necessary between the part and the for extreme toler-
very complex, tolerances are very tight
components within it. This technique has ances, electroform-
and time to prototyping and production Virtually all materials can be etched,
been used successfully in many technical ing is very effective.
is very short. although some are etched more easily
applications. Compared to other
than others. Etching is basically rapid,
metal forming pro-
Process outline controlled corrosion. Thus corrosion-
cesses like laser cut-
The PCM manufacturing process begins
resistant materials are difficult to etch Intricate, thin PCM parts ting, photo etching
and require extremely corrosive etchants.
by cleaning the metal and coating it The resolution of etched parts depends or stamping.
However, many materials such stainless
with a light-sensitive resist. The coated on material thickness and thus the most
steels, beryllium copper, nickel alloys and
sheet is then exposed to ultra violet brass, used commonly in manufacturing, intricate parts are fabricated from the For more information on the local
light through the photo master from can be etched readily by using aqueous thinnest materials. Photo etching has manufacture of custom etched precision
both sides, hardening the photo resist been the most general method for micro and intricate parts from Shimifrez Inc.,
solutions comprising ferric chloride. go to http://ept.hotims.com/40521-69
where exposure takes place. The unex- metal fabrication. This method needs a
posed areas are developed away, thereby
removing the resist and leaving the metal Precision products
bare where etching will occur. Etching PCM has provided a major, rapid-
solution is sprayed under pressure onto response service to supply components to Pitfalls of counterfeit-part epidemic exposed
the top and bottom surfaces, accurately the microelectronics, mechanical and elec- Companies attempting to manage the growing challenge of counterfeit electronic com-
producing the component by removing tronic engineering industries over the past ponents face a range of government- and industry-related pitfalls that make it virtually
the unwanted metal. The resist is then several decades. The demand has been impossible to eliminate all risk associated with the plague of fake parts, according to
removed to leave burr- and stress free for thin (< 1mm thick), complex, preci- experts speaking at the 2012 ERAI Executive Conference held in Las Vegas last month.
precision components. sion parts at an economic price. Leading The event was co-hosted by IHS.
examples can be items such as sieves and Speaking to a sold-out crowd of more than 300 industry participants, presenters
Precision Photo Etching meshes, shims, washers, optical encoders from information providers, standards organizations, defense contractors and distribu-
and filters, EMI/RFI shielding enclosures tors detailed the challenges associated with the rising tide of counterfeit and fraudu-
Inexpensive and (folded boxes), belts , sputtering and lent devices. While much of the discussion focused on the impact of fake parts on the
quickly-produced deposition masks to name a few.
military/aerospace sector amid new defense department regulations, the presentations
Photo tools, used in photo-chemical also examined the effect of counterfeits on the broader commercial electronic markets.
machining, replace conventional steel Micro engineering The scale of the counterfeit problem has grown dramatically in recent years, with
tools and dies. Photo tools can be gen- products reports of fake parts quadrupling from 2009 to 2011. Supply chain participants in
erated in a matter of hours from a cus- 2011 reported 1,363 separate verified counterfeit-part incidents worldwide, a fourfold
tomer-supplied CAD drawing or data file. PCM is now also used to fabricate com-
ponents used in micro systems technol- increase from 324 in 2009. Much of the counterfeit-parts problem can be traced back
Prototyping cycles can be reduced from
ogy and micro electro mechanical systems to the enormous amount of electronic waste (e-waste) generated each year, according
weeks to days compared to hard tooling.
(MEMS), medical diagnostic equipment to Bob Braasch, senior director, supply chain, for IHS.
and biomedical engineering applications “People don’t hold onto their old electronic devices,” Braasch told the event attend-
Flexible and fast such as body nozzle heads, X-ray light ees. “A three-year-old cellphone is ancient, so people are constantly upgrading to the
From initial tooling to finished parts, choppers and grids to IC leed frames for latest device. As the world economy improves and as technology continues to develop,
the entire photo etching cycle can be semi conductors, gimbals and micro chan- people increasingly will be looking for the latest technology. All of this electronics
completed in days. Given a normal back- nels are some names to declare. consumerism translates into e-waste.”
log, typical lead times for new parts Braasch noted that 58% of e-waste generated by the US is shipped to developing
are 2-3 weeks. Often, repeat orders can Aesthetic products countries. All too often, electronic components such as semiconductors are culled
be processed more quickly. Prototypes from this waste and then returned to the US and other developed countries in the
orders may be done in several days or In addition to the above, PCM can form of counterfeit parts. As the number of counterfeit parts has grown, government
even hours. provide parts with intrinsic aesthetic
regulations covering fake parts have grown more stringent. The US National Defense
value and is much used for the produc-
Consistent tolerances tion of jewellery, signage or decorations
Authorization Act (NDAA), which was signed into law on Dec. 31, imposes strict regu-
The photo tool is the foundation of and name plates. Very often, the etching lations and severe criminal penalties on counterfeits supplied for government military
accuracy. A photo tool is like a stencil. process is combining with electroplating, and aerospace programs. While this phenomenon is impacting all electronics market,
Its only working exposure is to light. So anodising or painting processes to give including consumer, communications and computing devices, much of the attention has
there is no tool wear that needs to be additional colour and difference. been focused on defense, due to the NDAA.
full online product listings at ept.hotims.com