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Tom
05-18-2002, 01:46 PM
Sec. 205a. - Congressional statement of findings


The Congress finds as follows:
(1)

The United States was an original signatory party to the 1875 Treaty of the Meter (20 Stat. 709), which established the General Conference of Weights and Measures, the International Committee of Weights and Measures and the International Bureau of Weights and Measures.

(2)

Although the use of metric measurement standards in the United States has been authorized by law since 1866 (Act of July 28, 1866; 14 Stat. 339), this Nation today is the only industrially developed nation which has not established a national policy of committing itself and taking steps to facilitate conversion to the metric system.

(3)

World trade is increasingly geared towards the metric system of measurement.

(4)

Industry in the United States is often at a competitive disadvantage when dealing in international markets because of its nonstandard measurement system, and is sometimes excluded when it is unable to deliver goods which are measured in metric terms.

(5)

The inherent simplicity of the metric system of measurement and standardization of weights and measures has led to major cost savings in certain industries which have converted to that system.

(6)

The Federal Government has a responsibility to develop procedures and techniques to assist industry, especially small business, as it voluntarily converts to the metric system of measurement.

(7)

The metric system of measurement can provide substantial advantages to the Federal Government in its own operations


A Capsule History

The United States is now the only industrialized country in the world that does not use the metric system as its predominant system of measurement.

Most Americans think that our involvement with metric measurement is relatively new. In fact, the United States has been increasing its use of metric units for many years, and the pace has accelerated in the past three decades. In the early 1800s, the U.S. Coast and Geodetic Survey (the government's surveying and map-making agency) used meter and kilogram standards brought from France. In 1866, Congress authorized the use of the metric system in this country and supplied each state with a set of standard metric weights and measures.

In 1875, the United States solidified its commitment to the development of the internationally recognized metric system by becoming one of the original seventeen signatory nations to the Treaty of the Meter. The signing of this international agreement concluded five years of meetings in which the metric system was reformulated, refining the accuracy of its standards. The Treaty of the Meter, also known as the "Metric Convention," established the International Bureau of Weights and Measures (BIPM) in Sèvres, France, to provide standards of measurement for worldwide use.

In 1893, metric standards, developed through international cooperation under the auspices of BIPM, were adopted as the fundamental standards for length and mass in the United States. Our customary measurements -- the foot, pound, quart, etc. -- have been defined in relation to the meter and the kilogram ever since.

The General Conference of Weights and Measures, the governing body that has overall responsibility for the metric system, and which is made up of the signatory nations to the Treaty of the Meter, approved an updated version of the metric system in 1960. This modem system is called Le Système International d'Unites or the International System of Units, abbreviated SI.

The United Kingdom began a transition to the metric system in 1965 to more fully mesh its business and trade practices with those of the European Common Market. The conversion of the United Kingdom and the Commonwealth nations to SI created a new sense of urgency regarding the use of metric units in the United States.

In 1968, Congress authorized a three-year study of systems of measurement in the U.S., with particular emphasis on the feasibility of adopting SI. The detailed U.S. Metric Study was conducted by the Department of Commerce. A 45-member advisory panel consulted with and took testimony from hundreds of consumers, business organizations, labor groups, manufacturers, and state and local officials.

The final report of the study, "A Metric America: A Decision Whose Time Has Come," concluded that the U.S. would eventually join the rest of the world in the use of the metric system of measurement.

The study found that measurement in the United States was already based on metric units in many areas and that it was becoming more so every day. The majority of study participants believed that conversion to the metric system was in the best interests of the Nation, particularly in view of the importance of foreign trade and the increasing influence of technology in American life.

The study recommended that the United States implement a carefully planned transition to predominant use of the metric system over a ten-year period. Congress passed the Metric Conversion Act of 1975 "to coordinate and plan the increasing use of the metric system in the United States." The Act, however, did not require a ten-year conversion period. A process of voluntary conversion was initiated, and the U.S. Metric Board was established. The Board was charged with "devising and carrying out a broad program of planning, coordination, and public education, consistent with other national policy and interests, with the aim of implementing the policy set forth in this Act." The efforts of the Metric Board were largely ignored by the American public, and, in 1981, the Board reported to Congress that it lacked the clear Congressional mandate necessary to bring about national conversion. Due to this apparent ineffectiveness, and in an effort to reduce Federal spending, the Metric Board was disestablished in the fall of 1982.

The Board's demise increased doubts about the United States' commitment to metrication. Public and private sector metric transition slowed at the same time that the very reasons for the United States to adopt the metric system -the increasing competitiveness of other nations and the demands of global marketplaces -- made completing the conversion even more important.

Congress, recognizing the necessity of the United States' conformance with international standards for trade, included new encouragement for U.S. industrial metrication in the Omnibus Trade and Competitiveness Act of 1988. This legislation amended the Metric Conversion Act of 1975 and designates the metric system as the "preferred system of weights and measures for United States trade and commerce." The legislation states that the Federal Government has a responsibility to assist industry, especially small business, as it voluntarily converts to the metric system of measurement.

Federal agencies were required by this legislation, with certain exceptions, to use the metric system in their procurement, grants and other business-related activities by the end of 1992. While not mandating metric use in the private sector, the Federal Government has sought to serve as a catalyst in the metric conversion of the country's trade, industry, and commerce.

The current effort toward national metrication is based on the conclusion that industrial and commercial productivity, mathematics and science education, and the competitiveness of American products and services in world markets, will be enhanced by completing the change to the metric system of units. Failure to complete the change will increasingly handicap the Nation's industry and economy.

Lameris
07-17-2002, 11:11 AM
Tom,

I was discussing your metric activities Sunday with the new Director, Henry Oppermann, and the new Supervisor, Ken Butcher, of the metric program at NIST. I have worked with these gentlemen for many years in the National Conference on Weights and Measures and I am very excited about the new emphasis NIST is placing on metrication.

I wanted to let you know they are interested in the efforts of PCBstandard.com and how to best get the engineering community to work in the metric environment. (NASA's spacecraft hitting Mars created more interest in metric by NIST too)

Keep on promoting metric, it's the right way to go!

Gary Lameris

Tom
07-17-2002, 11:54 AM
Gary,

That's good news. Here is where the world of PCB design layout is at on the subject......
Even though 99% of the world uses metric units, I have discovered that for the past 30 years most of those countries designed PC Boards using Inches. This makes a lot of sense since most of the available components 20 - 30 years ago were mostly Inch Pitch devices - like the DIP14.

A PCB designer will adapt to whatever standard is necessary to get the job done in the most efficient manor, regardless of the base units their country uses.

When I developed the CADPRO libraries in Inches, I was forced to because the majority of the part pin pitches were Inch based. Now that the standards groups have finally switched to metric, component manufacturers are also switching to metric.

The one and only reason why pcbstandards.com has a metric library is because about two years ago we realized that the majority of the parts in our PCB layouts had metric pin pitches. This made it difficult to place and route in Inches. Also, even if the pin pitches were Inch based, the manufacturers started dimensioning everything in metric and you had to constantly use a calculator to convert the numbers to inches. (Big Hassle)

The electronics industry is in a transition period where some parts are metric and some are still inches. This period is very frustrating and it makes our job more difficult.

Basically, PCB designers will use whatever units the component manufacturer uses. For instance, right now the 0.050" (1.27mm) pitch BGA is slowing down the Metrication process because it's an inch pitch part. When all the Inch Pitch parts go away, Metric Units will completely take over the electronics industry. And then you will see PCB design productivity skyrocket.

Colorado-PC-Dude
07-17-2002, 04:39 PM
Metric Units will completely take over the electronics industry. And then you will see PCB design productivity skyrocket.

Tom,

I have to disagree with the productivity aspect (I know, big surprise <G>). I've found that off-grid pins have very little effect on the boards we do here. Granted they are not terribly dense and compact but that seems to be more the norm (outside of handheld devices and some computer products). I have learned to start routing from the off-grid pins or to just get close and double-click to finish the route. I fall into those "do whatever it takes" guys.

Don't get me wrong, metric is the way PCB design is headed and like it or not we'll all be using it before long but, the metric system will not become commonplace until people start thinking in metric ("go about 3 km and turn left" instead of "go about 2 miles and turn left").

Ben

Tom
07-17-2002, 05:04 PM
Ben,

What I really meant by "Increasing Productivity" was that once we completely convert to metric we will have only ONE measurement system to deal with. Right now we're getting data sheets in both Inch and Metric and it's slowing down the process because you have to convert one or the other. For all those who design in inch units and get metric component datasheets, that's a lot of conversion going on. I've heard of building parts in metric and putting them in an inch design and that's OK if you're not interested in perfection.

We have done tests where every part pin falls on a 0.05mm grid. Every trace and via is on that same grid too and all pad sizes are in increments of 0.05mm. This has improved every aspect of the layout, including the turnaround time.

We have also converted all of our documentation to metric and this has streamlined our processes of maintaining documentation.

One last thing, our Government has proof that industries that have made the metric transition are more productive (Mainly because metric a much easier measurement system to work with). The U.S.A. version of metrication was to break the Inch into 10ths. That helped increase productivity levels, but it was not the real solution.

Colorado-PC-Dude
07-18-2002, 03:38 PM
Tom,

Now I understand what you mean about the productivity level. I have never bothered converting metric parts to inch. Way too much time consumed over something the software is supposed to (and does in my experience) handle. The world is going metric and the U.S. will certainly be dragged (kicking and screaming in most cased) along. I'm not certain that metric is the perfect solution but neither is imperial. At the end of the day, if I can use the system to get the job done, I'll use it.

The BenMetric system. Base measurement units divided into 2,520 equal sub-units. Why 2,520? It's equally divisible by any interger number 1-10. <G>

Ben

Tom
07-18-2002, 04:27 PM
Ben,

I've got an interesting fact about the size (how many bits of data) of a PADS database.

We took a 6,000 pin PADS file that was totally metric. All the pad and drill sizes were nice metric numbers. Same with the traces, vias and routing grid. We changed the units to Inches and the database quadrupled in size. It went from 2MB to 8MB.

If you want to keep your database size small, I would not recommend mixing technologies. I.E.: Building parts in metric and putting them in an inch design.

When you have a 1mm feature and you convert that to inches its .03937". Your ASCII database is completely made up of numbers. Use small numbers and you'll get a small database.

Colorado-PC-Dude
07-31-2002, 02:08 PM
Tom,

Good point about database size. I don't have a problem with metric (hey, I want a house in Canada) but the boss and the AutoCAD folks do everything in inches. Until they change I'm stuck with inches. I can't even talk to most of them in metric 'cause they keep asking "how much is that?" I'm sure I could take the board outline they give me and convert to metric there but all it would do is confuse a bunch of people stuck in a rut so deep they can't watch a sunset. <G>

Oh well. 12-18 months from now it'll all be moot anyway!

Ben