Metal whiskering

Do you know that not only mice and felines grow whiskers? Metals do too! Surprise surprise! To system and electronic engineers however this is an unpleasant surprise, a nightmare that they wish never will happen in their products. This phenomenon gain so much attention that high tech companies such as Lockheed Martin and NASA are still trying to understand it.

The removal of lead from solders increases the chances of tin whisker occurring. The phenomenon of whiskering had caused multimillion havocs, including the false alarm of Millstone nuclear plant, Swatch watches recall and the lost of Galaxy IV satellite (image taken from The Guardian).

Pro/ENGINEER - making edges more visible

If you are a Pro/ENGINEER user who finds the fact that the model's edges are not easily distinguished and causing features hard to find, then you may try this option to make the edges more prominent.

A sample 3D model in the original settings (above), with the circled area zoomed in (below).

Bimetallic Coin – The Making

Singapore has just launched its third series of coins last month, with the $1 coin stealing the limelight with its bimetallic composition. A golden brown outer ring encased a chrome inner core, which in fact are respectively brass plated and nickel plated metal. Much as a coin calls to mind the buying and selling process, there are also engineering involved in the metallic item – the manufacturing of it.

The array of new Singaporean coins launched in June 2013, with the $1 bimetallic coin taking center stage in this article's discussion (images taken from Monetary Authority of Singapore website).

Indentation Hardness

Among the three hardness types shared in the previous article, indentation hardness is the one which most engineers are familiar with. In fact, I bet that the general reply to the definition of hardness matches that of indentation hardness so much so that they are interchangeable in most discussions. Even engineering textbooks seldom mention indentation hardness as a separate topic – it is instead discussed as a hardness topic without an in-depth subtopic on other hardness types. 

Ball indenter used for Rockwell hardness testing. Different macroindentation test methods uses different indenter geometry and measures different dimensions of the indentation geometry (image taken from Instron).

Indentation hardness quantifies the resistance of a sample to material deformation, plastic deformation to be specific, due to the effect of a constant compressive load of a sharp object, hence the term “indentation”. In this test, a specific indenter is exerted onto the test material until an indentation is formed, of which dimension is measured and determines the hardness in accordance to a certain scale. 

For engineers personally involved in testing materials, it would be important to understand that most indentation tests have specific load rate and specific dwell time (the period in which the indenter load is held without moving), but not all of them are so. 

Hardness - How Hard Is Hard?

It is quite easy to say that a piece of metal is harder than a block of rubber, but how hard is hard? And is a cast iron harder than a stainless steel sheet? How would one find out information about hardness when you are reading the material properties from a specification sheet? 

In fact, when I read more into this property, it is not as simple as we usually would have thought, seeing that we use the descriptive term daily in our conversation. It could be said that: 

Hardness is a measure of how resistant solid matter is to various kinds of permanent shape change when a force is applied.

Diamond - not only were they a fascination with the ladies, they were also a fascination of engineers. With its reputation of being the hardest substrate ever known, it could cut through almost everything else. So how would you define the hardness of a diamond? (image taken from Jonathan's Fine Jewelers)

Gloss - Measurement of Gloss Part 1

As was established in the previous post, gloss is determined by the amount of light rays being reflected under specular reflection as opposed to diffuse reflection. The more rays reflected through the former method, the glossier the surface is. 

Taktik iPhone case designed by Minimal studio. The surface is described as glossy and although this image is (I suspect) a rendered image, the glossiness of the surface is still conveyed. For quality control, determining the item as meeting the expected gloss level is not acceptable through mere visual inspection (image taken from DesignBoom).

Gloss could be compared qualitatively by comparing reflection of an image off different surfaces. Surface exhibiting sharper reflection will be considered glossier. But this is only useful in a qualitative way, and only if both surface reflections are distinctly different. Different observant will have different sight and recognition capability as well, so this method is physiologically affected. This qualitative method will not suffice as a quality control method.

Gloss - A Perception of Surfaces Part 2

Unlike other physical measurements, gloss measurement is not as straightforward. But it isn't difficult either, once one understood how gloss is perceived and interpreted by the human eye.

Gloss is an aspect of visual perception of objects, and it is an attribute of surfaces. With this in mind, any material could be made to meet the requirement of any gloss level as long as the technology exists and the method economic. 

What in this picture makes you think that the car's exterior is "glossy"? What causes this term to come to mind? (image taken from Ziebart)

Gloss - A Perception of Surfaces Part 1

You take a look at the shiny metallic surface of a sleek sports car and you immediately thought of it as "glossy". You saw another car with a body which reflects none of the ambient lighting, absorbing everything like a black hole, and you think of it as "matte".

The glossy surface of an Audi TT (image taken from DeviantArt).

As easy as the word comes to your mind, how does one define "glossy"? This would be important to an engineer, since there has to be some way to control the quality of a surface, and control will not be possible without measurement, and no measurement without a solid definition.

Resin Identification Code

If you were to flip over most everyday items made of polymer, especially those which are disposable, you would have noticed the triangular sign with a number within and maybe some alphabets below. This is the Resin Identification Code, and unless you were working with a disposable consumer item and your company is committed to label their product accordingly, you may not have given it  a second's thought.

Image taken from Flickr (by holeymoon)

In order to address the recyclers' rising need for a clear indication of polymer used, Society of Plastics Industry, Inc (SPI) developed and introduced the identification code in 1988. This code is usually found in packaging and containers since these are the main targets of municipal recycling programs, seeing that they are one of common items encountered within residential waste.

The code is used solely to identify the plastic resin in a manufactured item. In fact, the triangular label with 3 twisting arrows along with the number within are commonly misinterpreted. The number within is an arbitrarily chosen number to represent the target plastics, and has nothing to do with ease of recycling. A higher number does not mean that the plastics is harder to recycle.

Folding Plug

Ever thought of the fact that however portable and sleek your laptop or latest gadget is, the huge rectangular plug with its 3 bronze pins sticking out totally diminishes the definition of "sleek"? No matter how innovation is done on every part of an electronic device, the plug is the one with almost nonexistent change as far back as anyone could recall.

Folding Plug can, as its name suggests, be folded and carried with greater mobility (image taken from The Guardian).

IP Rating - Immersion vs Water Jet

Followers of this series of articles on IP rating will recall that a higher number on the 1st numeral will satisfy the requirements of a lower number (i.e. IP6X will mean that it passes all requirements from IP1X to IP6X, revisit here if the reader is interested). It would be prudent to note that such is not the case for the 2nd numeral.

An IPX4 test in progress. The semicircle apparatus sprays water through tiny nozzles lining the inner circumference. The apparatus is designed such that the water spray will reach the product from all directions. Notice that the spray is constrained to the top of the product, and the bottom is free from its direct effects (image taken from Qualilab).

The reason behind this is the difference in test requirement: 

• IPX1 to IPX6K, and IPX9K requires the product to be subjected to a flow of water impacting on the product 
• IPX7 and IPX8 requires the product to be immersed in a body of water.

In order to understand the test requirements, it is essential to first understand the application of the product in an environment prone to water ingress. Water ingress into the product could come in two different scenario - the product could be sprayed on by water jets, or it could be dropped into a body of water for a determinate period of time. It is possible to be subjected to both scenarios throughout the product's application lifetime as well.

IP Rating - Waterproof

Just as it would be difficult to judge the level of protection of "dustproof" products, the same applies to the term "waterproof" - it gives no indication the level of protection the product affords apart from the fact that it is protected against water ingress.

A waterproof iPod Stereo Case - how would you judge the term? Will the casing be free from water ingress if submerged for more than 1 hour? How will an engineer judge the term "waterproof" for critical engineering equipment? (image taken from Marine Audio and Stereo)

The 2nd code element of the IP rating helps shed some light on the level of protection, which is listed in the below table. The technical term usually associated to this code element is "protection against liquid ingress".

Virtual Sky - Working under an Open Sky

Do you feel happy working under a clear blue sky as opposed to working in a stark office environment? Are your office employees shuffling around like zombies, or nodding off to a sleepy start in the conference room during meetings? Then fear not, for Virtual Sky will improve your employees productivity by providing them a chance to work under the infinite horizon of a clear blue sky! Or so that is how it goes...

This is how I work ever day (not the Party Rock way...)

Reading a recent news article from the technology section, I went in search for more information regarding this new innovation. Developed by Stuttgard-based Fraunhofer Institute for Industrial Engineering, or IAO in short (Institut fur Arbeitswirtschaft und Organisation) and exhibited in CeBIT Trade Fair in Hannover in March 6-12, 2012 was a matrix of ceiling lighting panels simulating clouds moving across a clear sky.

IP rating - IP5KX vs IP6KX

In the previous article, the first numeral code for an IP rating is mentioned as the protection level of a product against intrusion of foreign object, with IP5KX and IP6KX being the highest level. This article serves to elaborate on the latter requirements and how they differ from each other.

Dust test performed on a laptop within the dust chamber (photo taken from Espec website).

IP rating - Dustproof

Instead of claiming a product is 'dustproof', a better way of stating it is 'protection against foreign object intrusion', as is mentioned within IEC60529. There is a reason to it, as a product is not only in danger of being harmed by intrusion of dust or sand. One look at the grills of a table fan and it is not difficult to understand that its purpose is to prevent accidental and intentional (in the case of innocent infants) access to the dangerous rotating blades of the product. 

IP rating - Protection against Ingress

Sony Cybershot TX-5 (image taken
from Sony website).

Ever use products that failed because of water seeping into the interior? Or maybe sand jamming the moving parts? It is quite usual for products to be designed to be 'waterproof' or 'dustproof', but as an engineer, how do you know if they really are as they claimed, or what to look out for to know how 'waterproof' it is?

Engineered items are usually labeled as sealed against dust or water through a system known as IP rating. The IP code labeled on products and claimed in technical datasheet will provide users and buyers the degree of protection provided by mechanical casings and enclosures of electrical equipment against the following:

• protection against foreign objects (e.g. sand and dust)
• protection against effects due to ingress of water
• protection against access (accidental or intentional) by persons to hazardous parts inside the enclosure

Uni-signal - Traffic Light for Color Blind

If you think that there would not be any new designs that will surprise you the way i-whatever did, think again. Especially when you were rushing the red light. Surfing across the web in a lazy evening brought to my attention the design of Uni-signal, a traffic light with a slight variation from the norm. 

Uni-signal light - a new idea for the color blind (image taken from Yanko Design website).