We continue our discussion of ways to maintain your vacuum pumps by considering what needs to be done with blowers and diffusion pumps. Vacuum blowers (a.k.a. booster pumps) typically need little day-to-day maintenance, which normally consists of simply monitoring the oil level in the pump. The blower (Fig. 4) is used in conjunction with the mechanical pump to improve pumpdown rates and ultimate vacuum levels. By Dan Herring

A frequently asked question is, “How can I keep my vacuum furnace performing like it was when it was brand new?” This goes hand in hand with the question “How should you operate and maintain your vacuum furnace to maximize your investment and produce repeatable high-quality results?” The next few articles will provide tips for doing just this. By Dan Herring

When I worked for Carpenter Technology Corporation in their research center, we encountered several cases where chart ratings of specimens by their production lab yielded grain size ratings between 4 and 5 for a number of specimens on an order (these orders required tests on 20 specimens from different bars). When we re-tested them in the R&D center, we got similar chart ratings. But, when we actually measured the grain size, all ratings were between 5 and 6 on the ASTM E 112 scale. As the criterion for pass/fail was a grain size of 5 or finer (higher), this bias was important. Consequently, at a subsequent ASTM E-4 committee meeting, I conducted a “round robin” test. By George Vander Voort

In vacuum applications, cold traps are added to vacuum pumping systems either to remove unwanted contaminants (e.g. water, solvents, acidic or alkaline compounds) from the gas stream or to prevent pump backstreaming. These conditions can cause loss of efficiency or damage when introduced into or emanating from the vacuum pumping system.

In simplest terms cold traps work by sublimating a gas molecule, that is, by transforming the molecule directly from the gas phase to the solid (crystalline) phase thus bypassing the liquid phase. The gas crystallizes out on a cold metal surface often appearing as “frost” on the trap. By Dan Herring

It is erroneously believed by many that brazing filler metal (BFM) pastes need to be refrigerated prior to use, or for long-term storage. This has led to misunderstandings and difficulties in the handling and use of BFM pastes in many shops, and to incorrect, misleading product labels.

Having been involved in the manufacture and testing of brazing pastes for many years, I will categorically state that there is nothing inherent in the chemistry of brazing pastes that requires their refrigeration! Some industry specs (and some cartridge labels) still state: “This paste must be refrigerated prior to use”. This very misleading statement has caused some people to believe that the paste must be cold when used in order to perform properly. This is completely wrong! Cold brazing-paste is much stiffer and harder to extrude (which can also be dangerous), and serves no useful purpose. by Dan kay

For immediate release Oakville, Ontario, April 20, 2012 – VAC AERO International today launched its third redesigned website since 2007. In addition to featuring concise overviews on its vacuum furnace systems and coating services, VAC AERO offers hundreds of technical articles relating to the practice and application of vacuum processing and surface engineering in its…

Read More

Compared to many other metals and alloys and many other materials, such as carbides, ceramics and sintered carbides, aluminum and its alloys are low in strength and hardness. Aluminum is a soft, silvery metal with a face-centered cubic crystal structure, a hallmark of ductile metals. Its softness makes it somewhat difficult to prepare but the alloy is not sensitive to problems that plague preparation of magnesium and titanium, that is, a sensitivity to mechanical deformation that generates mechanical twins or Neumann bands. Aluminum, like chromium, niobium and titanium, is very corrosion resistant and a thin, transparent oxide film will form on a freshly polished surface. This film is responsible for its good corrosion resistance, but also makes etching difficult. Aluminum alloys contain a rather high content of intermetallic precipitates that contribute little to improving the alloys and may be detrimental. Contemporary four or five step preparation procedures are given for preparing aluminum and its alloys. Results are also shown for revealing grain size with Weck’s reagent, a useful alternative to anodizing. By George Vander Voort

Most brazing shops today will occasionally be given “rush” jobs by their good customers, and these brazing shops will usually do their best to respond as fast as they can, so that the customer will remain one of their best customers! No-one wants to do anything that would turn a good customer into an unhappy customer! by Dan kay

The long-standing practice by furnace manufacturers of offering only “stand-alone” pieces of equipment is changing. Today, some manufacturers, especially those who manufacture vacuum furnaces are capable of building completely integrated systems, which can be placed directly into the manufacturing flow. Of the choices technology available, only vacuum furnaces offer a true lean, green and agile solution. Let’s explore why.

To begin, we need an understanding of what being lean, green and agile is all about. Lean manufacturing (lean enterprise, lean production) is a production practice that considers the expenditure of resources for any goal other than the creation of value for the end customer to be wasteful, and thus a target for elimination. Working from the perspective of the customer who consumes a product or service, “value” is defined as any action or process that a customer would be willing to pay for. By Dan Herring

{source}<script language=”JavaScript”> function formCheck(formobj){ var fieldRequired = Array(“First_Name”, “Last_Name”,”Company”,”City”,”State”,”Country”,”Phone_Number”,”E-Mail”);var fieldDescription = Array(“First Name”, “Last Name”, “Company”, “City”, “State”, “Country”, “Phone Number”, “E-Mail” ); var alertMsg = “Please complete the following fields:\n”;var l_Msg = alertMsg.length;for (var i = 0; i < fieldRequired.length; i++){var obj = formobj.elements[fieldRequired[i]];if (obj){switch(obj.type){case “select-one”:if (obj.selectedIndex == -1 || obj.options[obj.selectedIndex].text == “”){alertMsg +=…

Read More