Resources

In parts 1 and 2 we talked about the Kinetic Theory of Gases and in particular, we showed how the movement of atoms affects principles such as molecular density, mean free path, and molecular velocity and how they are usedRead more...

Last time (The Fundamentals of Vacuum Theory – Part 1) we talked about the Kinetic Theory of Gases and how it can be used to calculate gas properties. We also considered the relationship between molecular density, mean free path, molecularRead more...

As in any discipline, understanding the underlying scientific principles has profound practical implications when properly understood. In this series of articles we will review the first principles of vacuum technology and explain them using real world illustrations. Most industrial vacuum systemsRead more...

For those of us who participate in the Heat Treatment group of LinkedIn (https://www.linkedin.com/groups/1855932), which by the way is 8795 members strong (!), an important vacuum processing question was recently asked and what follows is a stimulating exchange of ideas,Read more...

The automotive, aerospace, medical device and construction industries rely heavily on the use of fasteners to secure component assemblies. For example, medical devices (e.g. dental & orthopedic implants, instruments) employ literally hundreds of different types fasteners to hold their assembliesRead more...

Since brazing plays an important part in some of your company’s products, plan to have one or more of your people attend one of the high-powered, three-day (Tues-Thurs) seminars being held in 2015. Contact your people today to have themRead more...

As shown in my article last month, there are a number of very important steps that must be followed in order to insure good brazing, as shown in Table 1 of this article. Last month we looked at Criterion#1: ProperRead more...

Over the almost 45-years of my brazing career I have discovered that there are a number of fundamental principles that must be understood and followed if successful brazing is to occur. Over the next few months we will look atRead more...

A number of questions have come up in recent months about the use of electroless nickel plating as a brazing filler metal (BFM). To begin with, yes, electroless nickel (EN) plating can be an effective BFM, when properly applied. TheRead more...

This is the third in a series of articles dealing with brazing filler metal (BFM) in paste form, i.e., when the BFM powder is mixed with a suitable gel-binder to form an extrudable paste. As we’ve seen in the previousRead more...

Failures in metallic components may be caused by any of the following factors or combinations of factors: Design shortcomings Imperfections due to faulty processing or fabrication Overloading and other service abuses Improper maintenance and repair Environmental factors Not all failures areRead more...

Abstract Tool Steel Failure Examples and Metallographic Imagery below. Steels used for tools and dies differ from most other steels in several aspects. First, they are used in the manufacture of other products by a variety of forming processes. Second, tools andRead more...

Abstract Medical technology has developed many new devices that can be implanted into humans (in-vivo) to repair, assist or take the place of diseased or defective bones, arteries and even organs. The materials used for these devices have evolved steadily overRead more...

Abstract ASTM Test Method E 112 says it covers test methods to determine the average grain size of specimens with a uni-modal distribution of grain areas, diameters or intercept lengths. It says that these distributions are approximately log-normal. But, it doesRead more...

Abstract For many years, ASTM E384 has stated that the load range for microindentation hardness testing with both Knoop and Vickers indenters is 1 to 1000 gf. But, it also states that tests that produce a Knoop long diagonal or aRead more...

To maximize your investment and produce repeatable high-quality process results, it is mandatory to institute a thorough pump preventative maintenance program. In a pump’s normal operating life, nearly all unexpected vacuum pump failures can be prevented, and when carefully maintained,Read more...

Booster pumps (aka Roots blowers or intermediate stage vacuum pumps) fall into the class of dry, gas transfer pumps. As a dry pump, they do not introduce oil or water into the pumped gas stream. Gas transfer is accomplished byRead more...

Just as vacuum pumps can be considered the heart of the vacuum furnace, so too can the oil be thought of as its circulatory system. The selection and properties of the oil are critical to proper furnace operation. Pump oilRead more...

Every industrial vacuum furnace system uses a primary (aka mechanical) pump, which is also commonly referred to as a "backing" pump when either used in series with a booster pump, or used with both a booster and secondary ("high vacuum")Read more...

Last time we focused on the principles of operation of oil sealed rotary vane pumps including basic pump design, and pump oil. We now continue that discussion focusing on operational features and the inner workings of these pumps. Single Stage vsRead more...

Fig. 1 Pump down factor curve chart. Published in most editions of Edwards Vacuum product catalogs. Resistance to gas flow through components that make up a vacuum system has a considerable effect on the pumping speed and pressure obtainable within theRead more...

Fig. 1. Large oil diffusion pump Even as turbomolecular vacuum pumps have displaced most small laboratory sized oil diffusion pumps these days because of perceived ease of use and cleanliness, most high vacuum heat treating furnaces still rely on a largeRead more...

Figure 1. Pump down factor (F) graph When a vacuum system is designed it is often necessary to select a mechanical vacuum pump or pump set that will evacuate the chamber and associated piping in a certain amount of time. InRead more...

In the world of mechanical oil sealed rotary vacuum pumps there is a need for a variety of oils and fluids to suit the specific type of pump, its duty and the process it is used on. This discussion covers highRead more...

Fig. 1: Maintenance Plan for Microvac Pumps This article is written for vacuum pumps such as the oil sealed rotary piston pumps used on many heat treating and vacuum furnace applications. The same information would also apply to the oil diffusionRead more...

by Jeff Pritchard Maintenance procedures and safe working conditions are essential in maintaining vacuum furnaces as is proper preparation of components to be heat treated prior to charging to the furnace. VAC AERO International operates more than a dozen vacuum furnaces inRead more...

Savings can be achieved by improving energy efficiency, which reduces the amount of electricity consumed. Savings can also be easily achieved by making slight changes to the timing of this consumption, thereby reducing the peak electricity demand. Large heat-treating facilities areRead more...

For many years, VAC AERO has been performing welding and heat treating operations on a landing gear component for a popular turboprop aircraft. Because of the part design, the welding operation in particular is complex and challenging and often involves substantialRead more...

In recent years, the operating temperatures of land-based gas turbine engines have increased to improve efficiency.  As a result, greater demands are placed on the materials used in the manufacture of the engine components.  In particular, hot section turbine bladesRead more...

There are a number of factors that influence the development of a brazing cycle. These include such things as base metal and braze alloy composition, mass of the assembly and joint design.  However, each cycle is comprised of a numberRead more...