Vacaero

Manufacturers of heat treating and brazing vacuum furnaces and controls, complete hot zone and vacuum furnace retrofits, thermal spray coatings, plasma, HVOF and paint coating services.

VAC AERO Service Experience Trust
Canada FrançaisAccessibility |

The Oil Sealed Rotary Vacuum Pump

by

Since oil sealed mechanical vacuum pumps started to be commercially available in the 1920s there have been many companies making this type of pump. The oil flooded rotary piston vacuum pump runs at a slow rotational speed and is a heavy duty design. It has been manufactured for about 85 years.

In the early 1900s these pumps were relatively small at up to 40 cfm capacity. By the late 20s and early 30s the industrial revolution was gaining steam and the manufacturers designed larger capacity pumps to suit new applications. By the 1940s rotary piston vacuum pumps were offered in capacities up to 700 cfm. They are known for the ability to keep on running despite ingesting all sorts of contaminants. Kinney claims to have introduced the world’s first rotary pump in 1904, two years after the company was founded. The Kinney document I have just says rotary pump but I presume it was a rotary vane design as other documents say the rotary piston pump design was introduced in about 1909. In 1926 their popular model was the VSD-8811, later to be the KS-47. Current large models are called the ”KT” series.

Hot Zone Design for Vacuum Furnaces

by

The hot zone is perhaps the most critical feature of a vacuum furnace in terms of its effect on furnace performance and operating cost. There are a variety of hot zone designs and the choice of a design should be based on a careful analysis of specific processing applications. Most vacuum-furnace hot zones consist of four major components: the heating elements and the details on which they are mounted; the insulation package (or heat shields); a surrounding structure that supports the heating elements and insulation package; and a hearth that supports the load during processing.

Most vacuum-furnace hot zones consist of four major components: the heating elements and the details on which they are mounted; the insulation package (or heat shields); a surrounding structure that supports the heating elements and insulation package; and a hearth that supports the load during processing. A hot zone can be constructed in either rectangular or cylindrical form, with the latter being far more prominent in vacuum furnaces today. All hot zones are constructed in modular form for ease of installation into and removal from the vacuum chamber. BY JEFF PRITCHARD

Using Vacuum Furnaces to Achieve Lean, Green and Agile Manufacturing

by

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.

Energy Optimization in the Heat-Treat Department

by

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 are substantial electricity consumers. Specializing in vacuum heat treating and brazing for aerospace and other high-technology industries, VAC AERO International’s Oakville, Ontario, plant operates more than 24 vacuum, air and controlled-atmosphere furnaces. Included are three very large vacuum oil-quench furnaces, all of which result in substantial electricity consumption. Indeed, the company’s electricity costs have increased by more than 30% in recent years, thereby driving an effort to find lower-cost solutions. by Mark Passalent

Welding of High Strength Steel Landing Gear Components

by

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 substantial re-work.

In order to minimize the rate of re-work, VAC AERO undertook a comprehensive process review. The review determined that a minor design change could virtually eliminate re-work at welding. The assembly is a five-piece, tubular structure manufactured entirely from 4330V steel. It consists of a hollow tube approximately 1500mm long by 120mm in diameter, two fittings (upper and lower) that are TIG welded to each end of the tube and two backing rings that bridge the gaps between the fittings and the tube during the welding operation. BY JEFF PRITCHARD

Vacuum Brazing Techniques

by

Most base metals typically brazed in vacuum furnaces have a natural oxide “coating” that can inhibit the flow of brazing filler metals. 

Conversely, alloys containing appreciable amounts of reactive elements such as aluminum and titanium tend to form oxides at high temperatures which impede the flow of the brazing filler metal.  Many of the nickel-base superalloys fall into this category and the severity of the problem varies depending on alloy composition.  These materials should be brazed at high vacuum levels of 2 x 10-4 torr or better.  There are several reliable techniques for improving the brazeability of difficult to braze materials.  These include brush nickel plating of the joint surfaces, chemical etching techniques to remove aluminum and titanium from a shallow layer at the joint surface and using special aggressive braze filler metals with self-fluxing characteristics. The oxides of the less reactive metals like iron, nickel, and cobalt tend to dissociate (break down) under low pressure and high temperature.  Therefore, alloys such as the 300 and 400 series stainless steels, carbon steels and many tool steels can be successfully brazed in vacuum at relatively high pressures (1 to 50 microns). BY JEFF PRITCHARD

Joining Aluminum for Airborne Electronics

by

When joining aluminum for aerospace electronics, brazing often is the most practical choice for creating a continuous all-metal joint interface.

Because of its light weight and excellent thermal conductivity, aluminum often is the material of choice for assemblies that house or cool airborne electronics.

Aluminum’s properties are particularly important in combat aircraft. Weight minimization becomes a major design consideration for many components going into these aircraft. Thermal conductivity is especially important in the electronics packages because of the heat problems created by the dense packing of powerful systems in limited spaces. The complex aluminum enclosures, chassis and heat dissipators used in military avionics systems often are manufactured from numerous individual components, which must then be joined.

Selection of a joining process must be based on a thorough analysis of the service requirements and materials involved. For example, the joint’s mechanical strength properties often are critical. A structural joint usually requires good tensile and shear strength as well as resistance to fatigue from cyclic vibrations. Thermal conductivity of the joint is essential for heat exchangers and heat dissipators.

Electrical conductivity also may be important in some applications. In addition, the service environment must be considered, particularly when the joint will be exposed to temperature extremes, moisture or other corrosive media.
In enclosures, shielding sensitive electronic components from electromagnetic interference (EM!) often is critical. Certain joining processes provide joints with better EMI shielding characteristics than do others. by J.E. Pritchard & R. Laub