Electron Beam Welding

We just came across a very interesting article on electron beam welding and wanted to share it with  our audience.  A special tanks for Jon DeLalio and  EB Welding for sharing this content with us.

 

Why EB Welding Is Still Cutting Edge Technology – EB Industries

The first practical Electron Beam welding machine was put into use in 1958. Since that time many other welding methods, such as TIG, MIG, and Laser Welding have evolved technically.  However, Electron Beam (EB) welding is still the absolute best welding method for many critical, high-tech applications. Whether it’s creating high temperature exhaust nozzles for rockets or jet aircraft, or joining cutting edge 3D printed parts, EB welding has advantages that other welding processes simply don’t.

This article presents the top 5 reasons why Electron Beam welding is still as cutting edge as it was almost 60 years ago.

spike_for_blogA beautiful EB weld spike

EB Welding has the Deepest Penetration with the Smallest Heat Effected Zone.

At the top of the list of EB welding’s admirable qualities is unsurpassable weld penetration. A typical 150KV Electron Beam welding machine can create a weld spike in steel over 2” deep with a heat affected zone less than 0.2” wide. Simply put, there is no other welding process that can penetrate that deeply and precisely.

That EB welding can accomplish such a feat is due to the physics of the Electron Beam welding process.  Basically, EB welding works by shooting a high velocity beam of electrons into a part being welded. The electrons penetrate the material at the atomic level, imparting their kinetic energy as they strike molecules. The excited molecules heat up, resulting in a significant amount of energy in a very small area. The part is heated very quickly and very locally to the beam. Other welding processes rely mainly on heat conduction to transfer energy from the welding device into the part at the point where the welding device touches the surface of the material. Conduction, however, leads to the energy spreading out across the part as it heats, which limits penetration and increases the chances of melting or deforming the workpiece. Recently, there has been some work done to develop lasers that can approach the penetration of an electron beam. However, these lasers require exceptionally high power (close to 100 KW), which makes them both exceptionally expensive and exceptionally dangerous to work with. Electron Beam welding technology is proven safe and incredibly effective.

Welding in Vacuum is Ideal for Eliminating Weld Impurities.

A beam of accelerated electrons cannot be created or maintained in air because the electrons strike gas molecules and are deflected and scattered. Hence, Electron Beam welding must occur in a vacuum, and often this is viewed as a criticism: the welding chamber has to be pumped down and this takes time, etc. While this requirement is a complication, it is outweighed by the benefits that welding in a vacuum creates.

One of the biggest challenges in welding involves minimizing the impact of the molten metal interacting with ambient gases. These gases can react with the metal, creating oxides and other compounds that change the metallurgy of the weld pool and lead to impure welds. Often a cover gas is used to minimize these effects. However, nothing can compare to the cleanliness of welding in a vacuum.  In addition to being void of atmospheric gases, some impurities actually burn away during welding, and the result is the purest, cleanest weld there is.

Consider welding titanium: when heated, titanium becomes extremely reactive to the gases in air, resulting in carbides, nitrides, and oxides, which cause brittleness and can reduce fatigue resistance and notch toughness in the heat affected zone of the weld. The backside of the weld is also a problem as it is as prone to these problems as the front. But in the vacuum chamber of an EB Welder, pumped down to 10 -4 Torr, these problems simply disappear. The elimination of ambient gases combined with the energy density of the electron beam, easily creates very strong and aesthetically pleasing welds.  As one of our welders once put it, “Titanium welds like butter in an EB machine.”

Aerospace Control and Quality Standards

The EB welding process has, since its inception, been closely tied to the high tech military and civilian aviation industry as well as the manned space programs of the 1960’s — all of these technologies grew up together. Electron Beam welding was particularly applicable to aerospace applications not only because of the strength of the welds, but because the EB process lends itself to high quality machine controlled welds.

Because of the required vacuum, EB welding cannot be performed by hand. This means controlling the power of the beam and the motion of the part beneath that beam has to occur with some form of automation. In the early days, this was accomplished by electro-mechanical fixtures and manipulators. However, with the advent of computers, EB machines quickly evolved into full CNC control. For a design engineer, this meant that a very precise weld could be applied in a highly repeatable way.

Because of EB welding’s precision and automated repeatability, the aerospace industry developed quality standards to make sure the human elements of the welding process were tightly controlled. At first, these specifications were created by NASA, Grumman, Lockheed Martin, and other leading aerospace companies. Eventually, industry wide standards were developed, such as Aerospace Material Specification AMS 2680 and AMS2681. These specifications govern all aspects of the welding process, including joint design, material preparation, cleaning, testing, operator training, and process certification. EB welding has a precision, repeatability, and a “built in” culture of mil-spec high quality.

Superior Welding of Materials with High Thermal Conductivity or Unique Properties

The energy and thermodynamic characteristics of an electron beam are very unique. This ability to apply exceptionally high levels of heat energy to a very small area makes it the preferred welding method for many hard to weld materials.

Copper is one such material. Copper has superior thermal conductivity, which for some applications is a great attribute. But that high thermal conductivity also makes copper notoriously difficult to weld. High thermal conductivity creates challenges for heat conduction based welding methods such as MIG and TIG. These methods tend to melt the material on the surface of the weld area while not achieving significant weld penetration. Basically, the heat disperses quickly, either not heating the weld area enough, or overheating the entire part and causing it to melt and warp.

Laser welding is perhaps an option, but weld penetration is limited by not only thermal conductivity but also reflectivity. The amount of power a laser can apply to a work piece is limited by the reflectivity of molten metal. Essentially, the weld pool becomes a mirror reflecting energy away, again resulting in poor penetration or the over application of power, which can result in melting and distortion of the part. For copper, EB welding is often the most feasible option.

As mentioned earlier, a typical high voltage EB machine can obtain a weld penetration of about 2” in steel. This same machine can weld about 0.75” deep in aluminum and 0.5” in copper. As in steel, the welds will again be very narrow with a small heat affected zone.

EB welding’s unique ability to throw a lot of energy into a very small area also means that it is a great option for welding dissimilar material combinations where different melting points or conductivity might be a problem, or welding alloys that are crack sensitive or prone to porosity. 3D printed materials are particularly well suited to EB welding. Typically, metal additive manufacturing relies on melting a powered material into a solid. This method tends to create voids within the material lattice of the part. When welded, these voids, combine causing significant porosity in the weld. With careful control, an Electron Beam welder can join parts with minimal porosity issues.

EB Welding is Affordable.

EB welding can also be a very cost effective joining technology. It is true that for very large parts or complicated weld paths EB may not be the best option. Parts have to fit in a vacuum chamber and the welding beam has to be able to follow the path of joint. A trained and certified stick welder is very hard to beat from a versatility perspective. However, for smaller parts and high volume repeatable welds, EB can be amazingly efficient.

As an example, the welding of precision gears for the commercial aviation or medical device industries is a great application for EB welding. Gears for these industries require exceptional quality in high volume and at a low cost. In a typical gear assembly, the gear itself is made from a hardened alloy while the shaft or base is made from a less expensive and lighter alloy. EB welding’s excellence at joining dissimilar materials comes into play at this point. Making the weld strong and pure isn’t an issue, and fortunately, with a bit of well-engineered tooling and a degree of automation, these high quality welds can be achieved with very short cycle times and low cost.

For certain applications, the quality to cost provided by automated Electron Beam welding is impossible to beat.

Almost 60 Years Old and Still Going Strong

Electron Beam welding was developed in the late 1950’s, came of age during the 1960’s, and today is a tried and true technology that remains unsurpassed for weld penetration, weld purity, and precision repeatability. The process is highly standardized, with a tradition of high quality baked in. However, the EB welding process also has proven flexibility, adapting with the times such that it is an important part of even the most modern of manufacturing technologies.

Electron Beam welding: cutting edge since 1958.

Cho Bond Adhesives

If any our our readers are looking for Cho Bond Adhesives for their conductive adhesives needs, we suggest checking out Marketing East. Id you are looking for any of the following types fo Cho Bond Adhesives, visit the site or call them for more information

 

Cho Bond 1030

Cho-Bond 1029

Cho Bond 584

 

Do you have  general question about Marketing East, Parker Chomerics Cho-Bond® or any of our other products? . Would you like a price quote or to speak with a sales rep? Please use the Request a Quote page, or call Marketing East at 978-777-3837 or email  aaccettullo@marketingeast.com.

Centerless Grinders

Most plastic molding companies and machines have a need for centerless grinders within their operations.  Smith Renaud manufactures Precision Centerless Grinders with unmatched  performance and up time for  quality, cycle time, and machinery performance.

So what is centerless grinding and why is it important?

Centerless grinding is a  process that utilizes abrasive waterjet cutting  to remove materials from an article.  Centerless grinding is not the same as centered grinding because no spindle is used to center the article. The article is contained between  two grinding wheels and the speed of their rotation between  them determines the rate at which material is removed from the article.

For more information on centerless grinding visit the Smith Renaud website

 

 

Liquid Silicone Rubber Molding

Silicone rubber is made up primarily of sand or silicon dioxide.  Not beach sand of course but a specialty type of sand. This is not to be confused with other types of rubber. Liquid silicone rubber  or LSR as it is sometimes referred to is a specialty type of compound. It is often used for plugs, sels and other products where flexibility and toughness are important. Of course, resistance to heat is often a critical reason why LSR molding is used.

The liquid silicone rubber molding process is very exact and a very specialized area. It is similar to injection molding but not exactly the same. The silicone is formed rather than extruded.

In many ways it has good characteristics of both thermoplastic and thermoset materials. It is more flexible than regular PVC but not as expensive as other rubber compounds. Tooling is also simplified with LSR molding as cool silicone is injected into a hot mold. The compounds are purchased as Part A and Part b and then mixed and added to the mold.

 

 

 

CNC Grinding Machines

Sometimes in the plastic molding world, you need to grind down parts. Other times you have to adjust the machines and grind down metal parts.

Most  CNC  milling or cnc grinding machines are computer controlled vertical mills with the ability to move the spindle vertically along the Z-axis. When used with the use of round tools or a cutter it also significantly improves milling precision without impacting speed. This makes it much more cost effetive than engraving or other methods.

 

We have found tha Accura Technics is a well experienced in the design and development of CNC-grinding machines capable of sub-micrometer levels of precision. These levels of performance are utilized throughout Accura’s CNC-grinding machines for the plastic industry.

This  allows Accura to provide standard and special CNC-grinding machines products that offer maximum value, versatility and throughput. They  a system design philosophy that supports cost effective, space efficient designs while maintaining high performance standards.

 

If you are in the plastics field we would suggest you contact them to find out more about CNC grinding machines.

Molded Rubber Parts

Worcester, MA – Jefferson Rubber Works, Inc. (JRW), a leading manufacturer and provider of custom molded rubber parts, is now offering custom gasket cutting capabilities. Jefferson’s gasket manufacturing equipment allows them  to provide  quality Custom Fabricated Gaskets with quick turnaround and no tooling charges for most custom fabricated gaskets designs.

 

Jefferson utilizes the Atom Flashcut dieless knife cutting table and system. The ATOM Flashcut is commonly used for cutting a wide range of leathers, gaskets in their various forms (tang graphite included), rubber and it’s by products, open and closed cell foam up to 130mm in thickness, full range of composite materials including carbon fiber, Kevlar and pre-pregs, plastics, printed & laminated materials.

 

“We are pleased to be expanding our services and offering gasket cutting to both existing and new customers,” said Dave Pentland, President. The system gives Jefferson Rubber and its’ clients  faster and lower cost of production, rapid proto-typing and  pre-production runs, short-medium production runs become viable, rapid changeovers, no investment in traditional hard tooling, material savings – reduced scrap rate, and versatility.

 

Material that Jefferson  provide custom die cutting services includes non asbestos gasket materials, elastomers and TFE materials.

 

About Jefferson Rubber Works, Inc.

Jefferson Rubber Works is a leading manufacturer of high precision, custom injection, rubber molding products and has been for over thirty years.  Jefferson Rubber’s staff brings a broad spectrum of expertise and insight to every job.  The company offers complete in-plant engineering services, from prototype design to finished product.  Jefferson specialized in rubber gaskets, rubber grommets and rubber bellows… For more information call 508-791-3600 or visit the Jefferson Rubber Works website: www.jeffersonrubber.com.

 

Spindle Repair

Spindle repair is used to restore spindles to utmost efficiency. Machines and other applications use   spindles that are rotating mechanisms that work the cutting tool. The spindle is attached to the cutting tool or to a spindle-mounted system.spindle repair

Spindles are frequently used as a component in a machine and these parts often wear out and often require replacement.  A spindle is a round shaped unit made up of smaller components. Spindle bearings are very critical since they allow the spindle to spin and often wear out after frequent use.

Gros-Ite can arrange to have your spindle assembly shipped to its factory where it will be disassembled, inspected and evaluated. After our evaluation, a detailed quote will be faxed to you for your approval. All spindle parts are carefully examined for proper fits and geometry using the latest measuring equipment. Dimensions are returned to specifications to insure trouble free operation. All  spindle shafts are dynamically balanced to  the tightest tolerances in the industry.

There is no need to buy a new spindle. Spindle repairs performed by Gros-Ite make your spindle better than new while saving you time and money. No matter what type of spindle you have, trust Gros-Ite to inspect and repair your spindle needs. If you need a new spindle, we also offer stock spindles as well.

So now that you have been presented with the facts as to whether spindle replacement or spindle repair would be best for your needs. Either way, a properly operating spindle is a necessity to insure smooth operation of your equipment.

Laser Welding

laser welding
Laser Welding

We thought we would take a little break here from our usual molding and plastic talk and instead discuss laser welding.

Laser welding services  or laser beam welding (LBW) is a  technique that is  used to join several  pieces of metal by employing a laser. The laser  beam creates  a concentrated heat source which allows for very  narrow and  deep welds and high a high welding rate. Laser welding is often  used in high volume applications.

In case you did not know it, LASER is an acronym for “Light Amplification by the Stimulated 
Emission of Radiation”.

 

Welds created by laser welding are much stronger than conventional welds. Industries that may use laser welding include

  • jewelry repair
  • aerospace
  • medial device dental
  • electronics

 

Benefits of laser welding include

  • Processes high-alloy metals
  • open air use
  •  long distances with a minimal loss of power
  • Low total thermal input
  • Welds different  metals
  • No filler metals needed
  • No secondary finishing is needed
  • Highly accurate
  • Welds high-alloy metals

Disadvantages of laser welding include

  • Cools quickly which may cause cracks
  • Optical surfaces may be  damaged
  • High maintenance cost

Comparison  to Other Welding Processes

Similar to  Gas Tungsten Arc Welding, laser welding is a fusion process performed under inert cover gas, where filler material is most times not added. Similar to  electron beam welding, laser welding is a high energy density beam process. Laser cutting is different  from both GTAW and EB  or electron beam welding , because it does not need the workpiece complete an electrical circuit. Because  electron beam welding must be performed inside a vacuum chamber, laser welding may  offer a cost advantage over electron beam welding.

For more information on laser welding we suggest you visit EB Industries.

 

 

Compression molding

Many people are familiar with injection molding or plastic molding but not all are familiar

compression molding
Compression molding

with compression molding

Compression molding is a molding process whereby  the pre heated molding material, goes in  an open, heated cavity. The mold is closed with a  plug and  pressure is applied to force the plastic or rubber  into contact with all mold areas while applying heat and pressure. Compression molding uses  thermosetting  compounds and is is a high-volume, high-pressure method suitable for molding complex reinforcements.

Compression molding is often used for making electrical parts, flatware, gears, buttons, buckles, knobs, handles,  cases,  housings, and large containers.The advantage sof compression molding include  setup costs, quick setups, large size parts, intricate pieces and a nice  finish.

Companies that manufacture parts from compression molding include Reliance Engineering.

Injection molding machines with high positioning accuracy and high repeat-ability such as our hydraulic and electric ALLROUNDERs, are in demand for compression injection molding.  You must be careful  when selecting compression technology and for the design and layout of the mold.

Another company that can manufacture large plastic parts via thermoforming and heavy gauge thermoforming is Mayfield Plastics in Sutton Ma.

 

Rubber Grommets

Sourcing rubber grommets can be a tough task. The first hurdle is are you looking for standard rubber grommets off the shelf or do you need a custom rubber grommet.

 

If you are looking for standard rubber grommets you can probably find them form a major industrial distributor such as Grainger or a specialized distributor. I am sure you can find more from searching on Google.

 

If you need something custom the next hurdle is do you have enough quantity that a manufacturer will quote you with a decent minimum quantity. Often manufacturers will need thousands of parts to run a custom application.

 

You also need to know what type of material you  need. Rubber grommets can be made from  a variety  of rubber compounds including, silicone, Buna-N, Viton® Neoprene and EPDM.

 

You will also need to specify size. Rubber grommets range in size from .094 to many inches in diameter. You need to know the ID and the OD of your part. Some grommets are Mil spec as well.

 

We suggest you contact Jefferson Rubber for your custom rubber grommet requirements.