El blog de los útiles de control y la metrología

It is important to foresee the launching of checking fixtures early enough. Just like production means like moulds or matrixes are planned, why not planning the launching of checking fixtures at the same time?

Once we are over a barrel, we usually say things like: “I need something quick and simple because I will soon have my first samples”; “we need something to get out of trouble”???? Unfortunately, we listen to them too many times… and this forces us to look for a solution that will probably be far from being the best one. Good technical solutions and in some occasions the cheapest ones are those taken after a mature reflexion and a correct analysis, but emergencies never give good advice. And it is when one decides to produce something not adapted to his needs, and that finally is not valid, that it ends up being more expensive for the time and money wasted away… (Continua leyendo …)

Since the automotive sector is constantly submitted to pressure to reduce costs and deadlines (which come down to the same thing…), metrology and checking fixtures do not escape this trend. Dimensional metrology and quality control have always been present in the industrial production chain, and in the case of the automotive sector, the demands in that field have always reached the limits of what the latest technology could provide.

Over the past few years, measurement softwares have known a high-speed evolution, with the improvement of data recollection, displaying of files and geometries and software usability, the reduction of training and learning times, the automation of measuring processes through CNC programmes, the automatic calibration of sensors and far more other aspects that have considerably decreased the number of non-productive dead times. Some CAD softwares, like Catia V5R10, have even included a module enabling the direct interconnection with metrology softwares to make off-line programming easier. (Continua leyendo …)

Anodizing is an electrochemical process that can also be applied to checking fixtures to give them better aesthetic and mechanical properties finishings. This superficial treatment can only be carried out on aluminium; it is a forced oxidation thanks to which the base aluminium generates an aluminium oxyde protective layer (A12O3) on its surface. The thickness of this layer can freely range between a few microns to to 25 or 30 microns for protection anodizing and up to 100 microns for hard anodizing. This thickness is regulated by the UNE-38010 norm. The process consists in submitting the aluminium to a bath of acid, generally sulfuric. When the electric power goes through it, oxygen is liberated and goes to the anode that generates, by reacting to the aluminium, an oxyde layer which thickness varies according to the duration of the passing of the electric power. Then, the anodized aluminium is dived into hot water, to shut the pores present on the surface and thus finalise the process. The operational life of this finishing is proportional to the obtained anode layer thickness. (Continua leyendo …)

Following with the subject treated in the latest articles about The Checking Fixtures´ Ennemies, we will now deepen the second most important aspect to be taken into account.

Our experience through a lot of years has shown us that there are three types of part manufacturers that could be classified according to their idea of “checking fixtures”: (i) the first type of manufacturer is absolutely convinced of the fact that checking fixtures, gauges and measuring tools are an essential factor in all the production chain to get the quality level demanded by his customers ; (ii) the second type of manufacturer purchases checking fixtures, but more because it is one of the final customer requirements than for its own convictions, as if it were a mere step in the production process ; (iii) finally, the third type of manufacturer does not use checking fixtures at all as a prevention checking tool. He only purchases checking fixtures once a problem has appeared and he has to deal with a problematic solution he does not know how to fix.

Such different visions of “checking fixtures” are obviously related to the “quality check” policy that each company can have. A mere overview of the equipments, metrology and measuring tools used is enough to conclude that sometimes, there are abysmal differences. (Continua leyendo …)

In the article The Checking Fixtures´Ennemies, we indicated first this factor for its importance and influence on the other factors. It is by far the main pitfall we are hit by, because all the chain in the automotive sector is very sensitive to the final cost and its reduced margin. This is how things must be, but in a lot of occasions, when this factor is too restrictive, it is impossible to compensate it with imagination. In our article, we wrote that to have a part made, the companies must carry out a series of investments and expenses in design, means of production, inspection and quality checks, production management and follow-up, logistics… and much more aspects that make it very difficult in a lot of cases to have a total cost lower than the determined budget when arriving at the end of the chain. When this budget is overspent, there is always somebody in charge of taking the cissors to begin to cut expenses by order of priority, until reaching the objective: maintaining a positive margin. (Continua leyendo …)

Within their ecosystem, checking fixtures also have their predators. We can even be their main ennemies without being aware of it. To manage to produce a part, it is necessary to make a series of investment in the part designing, production means, and checking fixtures. The various aspects detailed bellow can have the effect of a time bomb: if it cannot be avoided or controlled, it will end up having all the attempts to check quality through checking fixtures brought down. Checking fixtures ennemies are, by order of importance:

• • • A low budget
    • An incorrect designing
    • A realisation timing too short
    • Flawed or non-existent information for final users
    • A bad execution
    • Poor quality materials or normalised elements
    • A bad maintenance

Throughout the next articles, we will give some more detail about each and every one of these aspects, and we will be able to analyse their importance.

Related articles: Cuaderno de cargas Photography: stock.xchng

When checking fixtures are used intensively, some automation must be carried out to reduce the cost for the checking of parts. Thanks to a minimal investment, the duration of the measurement process can be decreased by 90% by avoiding the introduction of the data obtained for the statistical study.

To get a sample of that type of checking fixtures, we created a copy of one of our customers´ conventional checking fixture - with his agreement - to use it as a sample and test bench. (Continua leyendo …)

Adobe Acrobat, aware of the necessities of the users of CAD, CAM and CAE programmes have just launched a new application enabling to create 3D PDF files to display existing geometries without the original CAD software.

This philosophy, that led to the creation of SpinFire, Autovue or 3D-Tool, displayers, meets an important need that checking fixture makers have. Before beginning the manufacturing of a checking fixture, the design must be validated by our customer, and even by the final customer, to check whether it complies with the requested functionality.

All these softwares enable to display a geometry coming from different CAD applications (UG, Catia, Pro.Engineer, Solidworks, Autocad, etc…), and also to check measures, set dimensions and finally get a 2D plan.

3D-Tools, the cheapest software with a price ranging between 150€ and 300€ according to the basic or advanced version, offers the interesting possibility to generate an executable file (.exe) that enables our customer to display the geometry without having to install any displaying programme, contrary to the others that need to be previously installed.

Acrobat Writer, the software necessary to generate PDF files, is sold at the price of €1,356. The reader to read the files, Acrobat Reader V8, is totally free. In all cases the other programmes (Autovue, Spinfire) have free displayers, and their installation is not really tricky.

Other related articles:Acrobat 3D y 3DXML (Frikingenieria)

The aim of this article is to redefine various metrology concepts for those who still have some doubts on that matter.

Any measurement result has an error, called measurement error, that cannot be known due to its nature. Indeed, a measurement is a comparison with a gauge reknown by all. Various factors have an influence during a measurement process:

• The object to measure
• The gauge with which it is compared
• The operator in charge of the measurement
• The measuring instrument
• The method
• The atmosphere in which the measurement is made
• etc.

(Continua leyendo …)

In order to avoid the oxidation of the metal parts of the checking fixtures – that is, fixations, supports, clips, etc - , an infinity of solutions are available regarding superficial finishings; yet, one of the most efficient ones as for quality, functionnality and aspect is “chemical nickel”. The Chemical Nickel overlap consists of an alloy of Nickel (90%) and phosphorus (10%).

It is chemically applied, since one of its main characteristics is the alloy uniformity, maintaining thus the tolerances of all the treated areas. As for checking fixtures, a 5-micron layer can be sufficient for the functionnality needed from them, so that it will only have a minimal impact on the manufacturing tolerances. As a non-porous product, it is highly resistant to corrosion and mainly triggers: