WHAT IS ETCHING?
Etching can be defined as: a process in which an acid dissolves the unprotected parts of a metal surface to create a pre-determined object.
The chemical etching technique originated in 15th-century sword-making and is best known from the art world, such as in the etchings of Rembrandt van Rijn.
It was not until the 20th century, when the first photoresists (photosensitive coatings) came on the market, that etching was able to develop into an interesting precision production technique. Initially for copper, copper alloys and (stainless) steel alloys, it was later also used for specialised metals such as beryllium, gold, molybdenum, tantalum, titanium and silver, among others.
Using precision etching, Etchform produces thin metal precision parts customised to drawing specifications for almost every industry, including aerospace, mechanical engineering, medical engineering and (micro-)electronics.
About MelSung
MelSung, Incorporated is in the international business of researching, developing, acquiring, manufacturing, marketing, and servicing, for optimum profit to us and our customers, specialty chemicals and systems for the metal and plastic finishing, electronics, graphic arts and offshore oil industries 每 in accordance with accepted ecologic and social considerations.we own photo etched workshop by ourslves.we are manufacture,not trader.
Our Customers
We will create an industry image that automatically causes people in the industries we serve to think first of MelSung.
We will justify their action by first thinking of the customers' needs 每 what's right for them makes it right for MelSung by supplying a total system including processes, know-how and services that assist in meeting all their needs.
Our People
We continue to believe in the supreme worth of the individual and the dignity of his or her work for the benefit of all. We will provide the opportunity for our people to fulfill satisfactorily their own personal objectives and ambitions and reward them in proportion to their contribution toward achieving the Corporate objectives.
We will continue to be a place of opportunity where people "have the guts to fail." We will encourage the entrepreneurs and innovators. We will continually challenge the goals, objectives, organization and all the operating and procedural aspects of our business and modify them when needed.
Our progress and your progress, our Company's long- term advantage and your long-term advantage, lie in our human resources. Other advantages that come about from technological improvements, the opening of new markets, lower costs, etc., all prove to be relatively short run. So, basically, it is the initiative, the will and the motivation that people bring to their work on which we rely for our survival and growth.
We will continue to try to attract new people who have creative and probing minds; people who will at times be disturbing 每 questioning policy and procedures. If we are wise, we will welcome it, resolve it, put it to work or forget it.
We will continue to expand with the best possible talent available and continue to train them, and ourselves, so that we each increase our ability to contribute to the Company's progress.
We will each strive to exemplify the MelSung Spirit of teamwork and cooperation throughout the organization which has been instrumental to our past and present growth as a corporation.
What We Expect From You
First and foremost, we expect of you a fundamental honesty 每 honesty with yourself, with your Company and with all those with whom you interact, whether they be associates within our organization, our customers or society in general. Character and strength have always been born of honesty and a willingness to face up to the truth of each situation as it arises.
Second, we expect and insist on hard work. An easy life, marked by the absence of difficulty, builds neither character nor happiness. We believe that self-realization of the individual is founded on accomplishment, which implies a willingness to make the sacrifices necessary to get the job done the way it should be done.
Third, we expect you to accept responsibility. Every assignment you will have carries with it a responsibility for accomplishment. Commit yourself to achievement which you consider beyond the scope of your talents and then program your effort to translate it into a reality.
Fourth, we expect of you a loyalty 每 loyalty to yourself, your family, your associates, your organization and our customers. We have always worked together as an organization and your own personal achievements will be measured in terms of the contribution you make to our joint effort.
Fifth, we expect you to demonstrate good judgment. Judgment is essentially an ability to appraise facts. Factual knowledge must come before good judgment. This means you must continually educate yourself on our Company, our products and our industry. In this way, you will have the material on which a sound appraisal of good judgment is based.
This is what we expect of you, and being in an extremely competitive environment, we have a real urgency in this expectancy.
What You Can Expect From Us
One, you can expect from us the fairest treatment of which we are capable 每 fair in respect to matters of compensation, fair in respect to working conditions and fair in respect to personnel policies.
Two, you can expect from us, as a Company, complete honesty in whatever we do. Your assignments will never compromise the principles of honesty and common decency which we also expect you, as an individual, to uphold.
Three, you can expect that we will provide assignments which will represent challenges to you 每 assignments which will enable you to grow toward your professional and personal objectives.
Four, you can expect that we will offer opportunities for advancement. Our desire is to grow from within.
Five, you can expect that we will be a demanding organization 每 demanding of your time, your talents and the best which you as an individual have to offer. In this way our company will grow and you will grow with it.
Perhaps all this can best be summarized in these words from an unknown author:
"Create mental pictures of your goals, then work to make those pictures become realities.
Exercise your God-given power to choose your own direction and influence your own destiny and try to decide wisely and well.
Have the daring to open doors to new experiences and to step boldly forth to explore strange horizons.
Be unafraid of new ideas, new theories and new philosophies.
Have the curiosity to experiment...to test and try new ways of living and thinking.
Recognize that the only ceiling life has is the one you give it and come to realize that you are surrounded by infinite possibilities for growth and achievement.
Keep your heart young and your expectations high and never allow your dreams to die."
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Photochemical machining (PCM) is an important process in the production of precise parts, mainly sheets and foils. Materials suitable for etching include: aluminum, brass, copper, magnesium, molybdenum, nickel steels, chromium, lead, nickel, silver, phosphor bronze, stainless steel and zinc.
Coating the metal sheet with photoresist sensitizes it. When this sensitized metal is put into the double-sided phototools and is exposed to UV light on both sides, an image is formed in the photoresist. This is then developed in a liquid formulation to form an adherent, durable image on both sides of the metal.
Various methods exist for the production of phototools. The most commonly used method is to produce a phototool of the correct size by using a laser photo-plotter to selectively expose a photographic film according to computer-aided design data.
Photoresists are UV light-sensitive polymers. The etching is performed by an acid cocktail that attacks the surface of the raw material on both sides. Before coating the metal with photoresist, the metal is thoroughly cleaned to remove all dirt, rust, greases and oils so that good adhesion to the photo-resist is obtained. The final element of the PCM process is to strip off the resist, ensure that the metal is clean and that the dimensional specifications requested have been satisfied.
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Advantages of photochemical machining
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Low-cost tooling
Quick delivery
Retention of mechanical properties
Step-and-repeat of design
Tooling changes at a minimum coast
Burr-free parts
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Technical Data
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Dimensions
Because of the nature of the etching process and the undercutting at the edges of the resist patterns on the surface, all dimensions, tolerances and configurations are functions of the thickness of the stock being etched, the material, and to a lesser extent, the process variables. In the section on tolerances and materials that follows, tolerances are given for a variety of metals, thicknesses, overall pattern sizes, etc. These are generally applicable to equipment, processes, metals and configurations currently being used. They do not, however, express the ultimate capabilities of photochemical machining.
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Metal Thickness
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Metal
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0.05 (0.002")
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0.2 (0.008")
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0.5 (0.02")
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0.8 (0.03")
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1 (0.04")
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1.5 (0.06")
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Tolerance ㊣
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Alluminium
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0.02
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0.03
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0.06
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0.09
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0.15
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contact
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Copper
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0.01
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0.02
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0.04
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0.06
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0.1
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chemograf
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Nickel
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0.01
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0.02
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0.04
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0.06
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0.15
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Steel
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0.01
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0.02
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0.04
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0.06
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0.15
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Stainless Steel
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0.015
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0.03
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0.08
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0.1
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Relationship of beval to matel thickness:
An etched equally from two sides, a bevel is produced. As a general rule, this bevel is approximately 10% to 20% of material thickness (T).
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1. Double-side etching
A=10% to 15%T
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2. Single-side etching
A=20% to 40%T
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Inner and outer corner radius (R)
Minimum inner radius = 75%T
Minimum outer radius = 50%T
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Relationship of hole size
to matel thickness:
As a general rule, it is normally stated that the diameter of a hole cannot be less then the matel thickness. This relationship however, does very as the matel thickness changes.
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Practical hole sizes attained
from sample thicknesses
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thicknesses (t)
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Practical hole sizes (D)
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0.0005"
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conect
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0.0010"
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Chemograf
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0.0020"
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0.0030"
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0.0050"
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0.0060"
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0.0070"
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0.0080"
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0.0100"
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0.0120"
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0.0200"
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0.0260"
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Center-To-Center Dimensions
Generally speaking, for small pieces, it is possible to etch Photo Chemically Machined parts which will tend to duplicate the center-to-center dimensions which exist on production artwork.
Because of limitations in rhe area of artwork. preparation, the following table IV gives practical center-to-center dimensions tolerances for finished parts.
Most of the tolerance is used up on material shifts in the etching process.
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The PCM Process
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1. Preparation on Raw material
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2. Lamination photoresist
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3. Masc attachment
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4. Ultra-violet light exposure
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5. Developing after removing the phototool
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6. Quality control
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7. Etching
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8. The product
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