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Vacuum System Leak Detection

Leaks in a vacuum system can be defined as an undesired gas flow and may be proven to exist as well as pinpointed for repair by applying leak detection techniques. When assessing vacuum system performance, leaks can be a frustrating aspect of operations. There are several classes of leaks:

True leaks – cracks or holes allow gas flow into the system

Virtual leaks – trapped volumes of gas which are slowly released within the system

Outgassing – gas flow resulting from techniques or materials used within the system.

Through the application of leak detection techniques, true leaks can often be pinpointed and repaired to bring the system within the desired vacuum specification.

There are several methods and tools to detect leaks; the most common of which is reduced pressure testing with a helium leak detector.

Helium is an ideal tracer gas for use in leak testing, because its light, small molecules easily flow through the tiniest of leaks. Helium is chemically inert, non-toxic and non-reactive, so it will not adversely affect the system being tested or the operator conducting the test. It is highly sensitive to detectors, and allows for the vacuum system to be tested while in normal operating conditions. Helium leak detectors are composed of a pumping system equipped with a small mass spectrometer.

To conduct a basic leak test, the detector is connected to the vacuum system and helium is applied along the outside of the vessel at likely leak sites. If a leak exists, the helium will pass into the system and travel to the leak detector. The detector will measure the partial pressure of the helium, and display the results as a flow rate. Regular calibration with a reference leak is necessary to properly maintain the integrity of the helium leak detector results.

Leak Detector

Leak detection can be a time-consuming process requiring a great deal of patience, but there are a few best practices that can make leak detection faster and simpler to perform.

  • Whenever possible, design the vacuum system with a valve to allow connection of a leak detector without requiring venting of the system.
  • Prior to assembly, test individual components, especially those that will be inaccessible when the system is in operation to streamline troubleshooting efforts when performing future leak testing.
  • Flanges and gaskets are likely culprits for leaks, and should always be inspected for dust, debris and damage prior to installation.

Contact Keller Technology to learn more about possible solutions to your most challenging manufacturing problems.

9 Main Processes Used for the Deburring and Finishing of Metal Parts

Deburring is the process of chamfering or rounding sharp corners formed on a metallic part during the machining process.  Deburring can also remove the raised edges and small pieces of material that may remain attached to a workpiece after it has been machined by a cutting tool or grinding wheel.  Finishing processes alter the surfaces of a workpiece to remove machining marks, scaling or pitting.  Finishing can also enhance the appearance or function of the part and prepare it for subsequent coating processes such as bonding, plating or painting.  Deburring and finishing are important process steps that should not be overlooked by the engineers and technicians designing and manufacturing component parts. 

polishing kit parts

Hand Grinding, Sanding, Lapping and Polishing

Manual processing of parts is still commonplace in today’s modern manufacturing facilities.  Many parts that are machined on sophisticated CNC equipment are still deburred and finished using an array of hand, ultrasonic and air powered tools.  Files, stones, knives, abrasive sheets/compounds, and specialized deburring tools are utilized by the machinist or tool maker to complete the fabrication process based on the part’s geometry and the requirements communicated by the engineering drawing.  Tedious and time-consuming hand work can add significant cost to a part; therefore if many identical parts are being produced, an automated deburring and finishing process is usually specified if possible.

Mass Finishing

Mass Finishing is a timed batch process that utilizes abrasive media and a rotating or vibrating process vessel to simultaneously deburr and finish multiple machined parts.  These machines process any surface that comes in contact with the media.  Ranging in size from small table top units used for processing rings and other jewelry to massive rectangular tub machines twenty feet long used for finishing aluminum aircraft parts. The processing vessels are generally fitted with a tough rubber liner to protect them from the media and prevent damage to the parts being processed.  There are countless combinations of media sizes, shapes and materials which are selected based on the machined part’s physical characteristics and how much material needs to be removed to achieve the desired surface finish.

Roller and Ball Burnishing

The process of burnishing is the plastic deformation of a surface due to sliding contact with another object.  There are many burnishing processes utilized by manufacturers today, however, the most common are roller burnishing and ball burnishing.  Burnishing does not remove any material, it is a small-scale forming operation that can improve the finish or hardness of the part’s surface.

Powered Brush, Belt and Disc Deburring and Finishing

These machines come in many shapes and sizes and utilize rotating abrasive discs, brushes and drums to process parts. They are best suited for sheet or plate material since parts are often transported through the processing equipment on a flat belt conveyor.  Some of these machines are engineered to produce the directional scratch marks known as a grain on flat sheet metal surfaces.  Robots arms can also be outfitted with compliant power tools and bonded abrasive media to process large 3-dimensional parts.  These robotic workcells are then programmed to deburr corners and finish surfaces in a repeatable and controllable fashion.

Abrasive Blasting

Solid particles of a selected abrasive media are accelerated, most commonly with compressed air, and directed by a nozzle so that they impact the part’s surface at a high rate of speed.  There are many different media materials, sizes and shapes that can be utilized depending on the hardness of the base metal and the surface effect desired.  Sand is a common and inexpensive material that is often utilized to clean and texture large metallic surfaces and prepare them for subsequent painting processes.  Glass beads, crushed walnut shells, dry ice and baking soda are examples of other media that can be used in abrasive blasting systems.  It is common for smaller parts to be placed into an enclosed cabinet for processing.  This glovebox enclosure contains the dust generated by the blasting process and protects the operator from the ricocheting media.  There are also robotic blasting systems and multi-nozzle machines available that automate the process and improve consistency and material removal rates.    

Electrochemical Deburring and Polishing

This is a method that finishes a machined part’s surfaces by means of anodic metal dissolution.  A part specific shaped tool is the cathode.  In conjunction with an electrolyte fluid, an anodic reaction is created between the tool and the part that removes surface material in a very precise manner.

Thermal Deburring

This process uses the ignition of a combustible gas within a pressurized chamber to remove burrs from machined components.  Because the burrs are much smaller than the component, they reach the auto-ignition point instantly and are vaporized in the oxygen-rich chamber.  An oxide powder is left across the component surfaces and may need to be cleaned prior to, or as part of subsequent coating processes.

Abrasive Flow Polishing and Deburring

The abrasive flow process uses the reciprocal flow of abrasive laden slurry to polish and deburr the surfaces and edges of a machined part.  Two vertically opposed cylinders pump the slurry back and forth through passages formed by the workpiece and special part specific tooling. This process is typically used to deburr and polish parts with complex internal features.

plasma treating metal parts

Plasma Surface Treatment

Plasma, the fourth state of matter, is a gas that’s been partially ionized and has been electrically charged with freely moving electrons in both the negative and positive state. Plasma flames can be used for pretreating surfaces of metallic parts prior to subsequent coating, printing or bonding operations. The plasma removes any foreign contaminants present on the surface of a material and also activates the surface at a molecular level significantly improving the adhesion characteristics of the base material.

Keller Technology is a world class manufacturer of vacuum and pressure vessels, process equipment, electro-mechanical sub-assemblies and complex machined parts.  Our well-equipped, state of the art manufacturing facility allows us to produce fabrications to exacting dimensional tolerances.

Contact us today with your most challenging fabrication and manufacturing projects.

Surface Finish Specifications and their Hidden Cost Impacts

When designing a custom machined component it is important for the engineer to define all of a part’s characteristics and effectively communicate them to the machinist or fabricator. This is usually done by creating and transmitting an engineering drawing that contains numerical dimensions which define the size and location of every feature of the part. It also communicates other important part attributes including the material type, hardness, allowable dimensional deviations, coatings, fabrication methods and other industrial manufacturing processes.

One of the more important requirements a drawing also defines is the surface finish or “allowable roughness” of the many surfaces of a machined part.  The surface finish can have a dramatic effect on the ability of the part to fulfill its intended function.  Surfaces that need to seal or contain a gas or liquid must be defined in a way that allows them to be leak-tight to the specified levels.  Surfaces that have relative motion between them may need to be low or high friction to function, as intended.  Even if the surface finish does not have an effect on the function of the part, there may be a purely aesthetic need for it to be improved during the manufacturing process.

Figure (a) above is an example of a drawing symbol as used on a drawing and figure (b) shows the meaning of each of the numbers and also the location of the lay symbol.

Roughness average (Ra) is the most commonly used parameter engineers utilize for defining the surface finish of a part. Ra provides an arithmetic average of surface irregularities measured from a mean line that lies somewhere between the highest and lowest points.
Surface comparators are available for many of the different manufacturing processes that produce a textured surface on a part. They are handy tools that allow an engineer to get a feel for the roughness of a surface at the most commonly specified Ra levels. This is a comparator for many of the common metal machining processes in use today.

If the fabrication shop is forced to use extensive light finishing cuts, surface grinding, polishing and lapping to meet the specified surface finish, it can double or triple the cost to produce the part. The addition of spot faces, grooves, reliefs, and raised bosses can be added to the product design in order to minimize the size of the surface area requiring extensive surface processing and inspection.

Producing very smooth and highly polished surfaces over large areas can be an extremely costly, manual process. This is generally accomplished with fine abrasive compounds, papers or tapes where the rate of material removal is very slow as compared to the primary machining processes that utilize a cutting tool to remove large amounts of material. If hand grinding and polishing is necessary, one way to reduce the cost of a part containing a highly polished sealing surface is to dimensionally define and minimize the surface area requiring the additional handwork. When specifying surface finishes, the engineer must analyze and understand the downstream time and cost impact of the roughness average (Ra) numbers that are called out on the drawing.

The knowledgeable engineers at Keller Technology Corporation can assist our customers with cost reduction, design for manufacturability and mechanical design optimization services. Keller Technology is a world-class manufacturer of vacuum and pressure vessels, process equipment, electro-mechanical sub-assemblies, and complex machined parts. Our well-equipped, state-of-the-art manufacturing facility allows us to produce fabrications to exacting dimensional tolerances.

Contact us today with your most challenging manufacturing projects.

High Speed Machining 101

High speed machining (HSM) has come a very long way since its conception in the early 20th century.  Early adoption of the concept was slow, but in the early 1980s, the HSM process got a jump start as aerospace companies started making investments in research and development to further advance the technology.  In the last 20 years, huge strides have been made in a relatively short period of time and HSM has now achieved widespread acceptance by today’s manufacturers. The future of high speed machining was envisioned by the process inventors when they discovered that after a certain point, increasing the cutting speed actually reduced the heat in the cut.  The graph below (Fig. 1) from Dr. Herbert Schulz’s “History of High Speed Machining” illustrates this phenomenon perfectly.

The dotted lines represent temperatures of various metals at different surface speeds.  Temperatures rise steadily with increasing speed until they peak and start going down with higher rates.  One of the big advantages of high speed machining is that at elevated rates of speed and feed, the chip is cut and evacuated so fast that it transfers little or no heat to the green workpiece.

The best way to describe modern high speed machining is the definition coined by Modern Machine Shop Magazine.  They stated that HSM “refers to making light milling passes at high spindle speed and feed rates to achieve a high metal removal rate.”

In practice, high speed machining is a collaboration of equipment, tooling, software, and techniques that machinists and CNC programmers use to continually improve machining efficiency in today’s modern machine shops.  Advanced computer programs running on relatively inexpensive and powerful computers have made many of these rapid advancements in efficiency possible.  What may have been considered HSM only a few years ago, could now be considered standard speed machining.

Some of the more common HSM practices, techniques, and tooling found in use today are:

  • Using a single pass by combining the roughing and finishing passes used in traditional machining.
  • Utilizing smaller diameter tooling at higher rotational speeds, moving at faster feed rates than the traditional large diameter, slower rotating tools.
  • Programing lower cut widths typically less than 15% of the cutting tool diameter.
  • Using High Efficiency Milling (HEM) strategies such as trochoidal milling
  • Selecting optimum spindle speeds that maximize stable milling zones.
  • Utilizing advanced machines, spindles, cutting tool materials, setting & balancing equipment and rigid work holding systems.

As a manufacturer of precision CNC machined parts and complex process equipment for many of the world’s largest OEMs, Keller Technology Corporation is continually improving our internal processes, tooling and CNC machining equipment.  Contact KTC today to discuss how we can handle your most challenging manufacturing projects.

What to Consider When Outsourcing the Manufacture of Medical Equipment Assemblies

For some producers in the medical industry, such as manufacturers of large, capital medical equipment, it may not be practical or possible to outsource the entire system. A medical device manufacturer can still benefit from outsourcing by selecting high level assemblies (HLAs) to outsource.

Here are five things to keep in mind when pursuing this approach:

  • Utilize a qualified contract manufacturer (CM). The CM should have a robust Quality Management System. Typically, companies will look for CMs that have facilities holding ISO 9001 and ISO 13485 registrations.
  • Provide clear, accurate documentation to the CM. It is vital that the manufacturing drawings, bills of materials (BOMs), work instructions, and test protocols are detailed and accurate. A joint review of all documentation by both parties before moving forward is critical; missing information, redlines, undocumented knowledge, and critical processes need to be captured.
  • Choose a CM with a well-developed supply chain and supply chain management system. HLAs for medical equipment are usually integrated from a diverse variety of components, and no CM can make everything. The ability to quickly, easily, and economically obtain required BOM components is key.
  • Establish responsibility for documentation control. In many cases, it makes sense for the CM to control the drawing package to update redlines, manage component issues, etc. Sometimes for regulatory reasons, the medical device OEM chooses to retain control over documentation. The most important thing is to define the scope of responsibility and ensure that procedures are clearly defined from the start.
  • Outsource assemblies at the highest level of integration possible. Outsourcing at the highest-level practical may simplify both the medical equipment manufacturer’s factory floor and supply chain. Place one purchase order and receive a fully-tested module ready to be integrated into the final assembly of your equipment.

By following these steps, you’re sure to enjoy a profitable relationship with your medical equipment assembly CM. Want to find out more about Keller Technology Corporation’s contract manufacturing services? Contact us today.

Building Vacuum Chambers for Laser Installations

Keller Technology Corporation’s comprehensive manufacturing capabilities afford us the opportunity to build complex and unique vacuum chambers for a variety of applications, including research equipment for universities and research institutions as well as the semiconductor and medical industries.

The chamber pictured will be installed at University of Rochester’s Laboratory for Laser Energetics (LLE) as part of a next-generation laser system capable of producing powerful, ultrashort optical pulses for a broad range of scientific experiments. The laser system, called MTW-OPAL, is a prototype for an even larger system that will be added to the existing OMEGA facility to reach record power densities (intensities) unachievable by any other means. For intensities of this magnitude, the technique of “chirped pulse amplification” is required. This technique was invented at the LLE in 1985 by Drs. Mourou and Strickland, for which they received last year’s Nobel Prize in Physics.

High intensities are reached by first stretching the pulse in time, amplifying it, and then compressing it back. At these intensities, all matter is ionized and therefore the optical pulses must remain in a vacuum. Keller Technology was responsible for building a key piece of the prototype system, the vacuum compressor chamber, which will contain the critical components at the end of the new MTW-OPAL laser for achieving petawatt power levels. 

The LLE of the University of Rochester is a unique national resource for research and education in science and technology. LLE was established in 1970 as a center for the investigation of the interaction of intense radiation with matter. The National Nuclear Security Administration (NNSA) funds LLE as part of its Stockpile Stewardship Program.

Along with vacuum chambers for high power laser installations such as MTW-OPAL, Keller Technology provides chambers for linac-driven x-ray band Free Electron Lasers (FEL’s) Synchrotron light sources, Neutron science, radio oncology equipment and more. Utilizing the latest in five-axis machining and robotic welding techniques, Keller Technology can provide vacuum chambers constructed of plated steel, stainless steel or aluminum.

How KTC Handles Workplace Safety, Material Handling, and Lifting

  • According to the Bureau of Labor Statistics, working with notably dangerous equipment is one of the leading causes of workplace injury.
  • There are four safe stages for every lift: preparation, lifting, carrying and setting down.
  • Consult with your employer’s safety team leader and shop supervisor to make sure you’re utilizing all lifting aids.

Since opening the doors of our first manufacturing facility in 1918, employee and workplace safety has always been the number one priority at Keller Technology Corporation (KTC). For over 100 years, our employees have safely utilized notably dangerous equipment in the workplace such as overhead cranes, chains, straps, and hand trucks to move, manipulate, and reorient heavy objects. According to the Bureau of Labor Statistics; these tasks combined are one of the leading causes of injury in the workplace. In 2001, it was reported that over one-third of time lost at work was the result of shoulder and back injuries.

Keller Technology Workplace Safety

There are four stages of every lift:

  • Preparation
  • Lifting
  • Carrying
  • Setting down.

Our trained employees carefully plan and execute every stage to minimize the risk of injury to themselves and fellow employees.

There are many resources available to help educate and prepare yourself for the type of lifting you are required to do. When planning a material handling task, consult your employer’s safety team leader and shop supervisor to make sure you’re correctly utilizing all of the lifting aides at your disposal.

Keller Technology’s facilities in Tonawanda, NY and Huntersville, NC are outfitted with modern material handling equipment and tools. Extensive training is completed by all shop personnel to prepare them for moving large heavy components, machinery, and tools on a daily basis. When employees know and practice good protocol for lifting, they are less likely to suffer from injuries caused by the handling of heavy objects.

Do you need a reliable, experienced staff to deliver a contract manufacturing project safely, on time and in budget? Contact us for a project quote.

Commonly Used Non-Destructive Testing Methods to Verify Component Integrity

  • The goal of Non-Destructive Testing (NDT) is to confirm structural integrity without damaging it.
  • NDT technologies utilize mediums like sound waves, lasers, magnetic particles, x-rays, vibration, electrical current, radio waves, special liquids, and gasses.
  • There are many highly sophisticated NDT methods to verify the integrity of a component, stock material, or system.

Choosing the right testing method is critical to evaluating the integrity of a component in an efficient and effective manner. Two options of testing for integrity of a component, stock material, or system are Non-Destructive Testing (NDT) and Destructive Testing. The goal of NDT is to confirm the structural integrity, conformance or functionality of a manufactured component or assembly, without damaging it. This allows the part to be used as intended after testing is completed, which in return saves you resources. Conversely, destructive testing damages a sacrificial part sample and is done as part of a statistical quality control program.

NonDestructive Testing Method

The names of NDT methods are often derived from the type of penetrating medium used or the scientific equipment needed to perform them. Modern NDT technologies utilize many different mediums, including sound waves, lasers, magnetic particles, x-rays, vibration, electrical current, radio waves, special liquids, and gasses. At Keller Technology Corporation (KTC), we utilize many different NDT processes. The type of tests used, and when we use them, depends on the engineering and manufacturing requirements of the particular part or assembly we are making. Three of the most common tests, that are used almost every day at KTC, are briefly described below.

  • Visual Testing (VT) – The most frequently used NDT inspection process at KTC. As the name implies, this process utilizes the visual observations of trained machinists, fabricators, toolmakers, engineers, and inspection personnel. To enhance the observation process, it is common for the inspector to utilize special lighting, optical magnification, mirrors and borescopes to inspect assemblies, surfaces, and welding zones for cracks, corrosion, damage, or misalignments.
  • Leak Testing (LT) – This NDT is typically used to verify that a pneumatic component assembly, ASME code pressure vessel or vacuum chamber is airtight within the defined parameters. There are four main types of leak tests:
    • Bubble leak testing – Generally, this test uses compressed air, a tank of water, or a soapy solution to form air bubbles at a leaking area of the assembly. The bubbles are then noted by the inspector as part of a visual testing process.
    • Halogen Diode testing – The Halogen Diode testing also utilizes a pressurized system of air and a halogen-based tracer gas. After a set period of time, a halogen gas “sniffer” instrument is used to detect and locate the presence of any leaks.
    • Pressure Change testing – This utilizes a “closed system” where the part is filled with air. A change in air pressure or airflow is detected by a sensitive leak test instrument over a defined period of time.
    • Mass Spectrometer Leak testing – This form of testing is a very sensitive detection process that can accurately detect extremely small leaks. The test can be set up a number of ways depending on the size and shape of the part under testing. In all cases, the detection of helium gas molecules by the test instrumentation determines the presence and size of the leak present.
  • Liquid Penetrant Testing (PT) – The basic principle of PT is that when a highly fluid penetrating liquid is applied to the surface, a part of it will penetrate into tiny fissures and voids will open to the surface. After waiting a prescribed dwell time, the inspector removes excess penetrant from the surface and applies a developer material. The trapped penetrating liquid will flow back out to the surface, contact the developer, and become humanly visible by standard or fluorescent light. This type of test will detect cracks that do not pass all the ways through the wall and become leaks detectable via leak testing. However, Liquid Penetrant testing does not work well with porous surfaces. It is imperative that the surface under test is very clean prior to inspection.

There are many more, highly sophisticated, non-destructive testing methods used to verify the integrity of a component, stock material, or system. At KTC, we take pride in knowing that our products meet or exceed our customers’ requirements for quality and workmanship. Contact KTC today for more information about our NDT capabilities and part inspection experience.

FABTECH Expo 2018 – Georgia World Congress Center

Keller Technology Corporation (KTC) was in Atlanta for FABTECH 2018, held November 6-8th at the Georgia World Congress Center. The expo featured the latest innovations in welding, forming, additive manufacturing, and surface finishing equipment. The show’s exhibitors displayed equipment in three buildings filling them with engineers, tradespeople, sparks, and smoke.

Keller Technology at FABTECH Expo 2018

Exhibitors’ booths were extremely busy from the start of the show and many of the machines on display had “sold” signs on them by day three.  Companies were demonstrating computer-controlled, fully automated, tube forming machines, painting, and welding robot work cells, laser marking machines, waterjet cutting systems, and CNC press brakes. Continuing the trend of highly sophisticated computer-controlled equipment, surprisingly there were six-axis robots performing precision grinding and polishing operations on complex curved surfaces on the exhibition floor. These robotic work cells utilized sophisticated, multi-axis, force feedback sensors and programming to do what operators were tasked to do only a few years ago.

Not all of the equipment on display at the FABTECH show were fully automated and computer-controlled.  There were plenty of machines on display that would fit well with the manufacturing operations of smaller fabrication shops that routinely process lower volumes of an unpredictable variety of parts. If you’re only building a few copies of a component, it is impossible to justify the capital investment and programming time of a fully automatic system. A machine that bridges the gap is a semi-automatic tube bender from Unison. It increases the overall throughput and also improves the accuracy and consistency of a manual tube forming operation.

Equipment at FABTECH Expo

There were also exhibitors offering products that were not equipment related. These included gloves, masks, clothing, grinding discs, abrasive belts, and weld process monitoring instrumentation. Our friends at Aquasol Corporation, whose products we use regularly at KTC, had a booth displaying all of their purging, atmosphere monitoring and cleaning products that help companies produce consistent and high-quality welds.

Aquasol Corporation at FABTECH EXPO | Keller Technology

Technology is rapidly expanding into areas of the manufacturing and fabrication industries where it has always been difficult to justify automation. With skilled tradesmen and tradeswomen in short supply, companies are investing in advanced equipment to increase manufacturing capacity and make their current employees more efficient. KTC is excited by this wave of change and continues to invest in people, training, and technology at both of our cutting-edge manufacturing facilities.

Do you need a reliable, experienced staff to deliver a contract manufacturing project on time and in budget?

7 Common System Types for Additive Manufacturing

  • There are a wide variety of Additive Manufacturing (AM) systems creating parts out of an assortment of materials.
  • Engineers are learning to design parts for new AM systems.
  • AM is changing the way products are being designed and parts are being produced.

Additive Manufacturing, or AM, is the process of creating a three-dimensional object directly from digital data. A part model, created using a computer and CAD software, is physically recreated, layer by layer, on the printer’s build platen utilizing feedstock materials in liquid, powder, filament, or sheet forms.

There are a wide variety of AM systems creating parts out of many materials, including polymer, plaster, metallic, glass, concrete, paper, ceramic, and biologics. From nanometer scale to the size of a house, AM is producing complex geometry and details that cannot be created by any other manufacturing process.

Engineers are learning to design parts specifically for these new AM processes, and it is changing manufacturing as we know it. Here are the seven categories of systems, as defined by the Additive Manufacturing Research Group, and a brief synopsis of each type:

  1. Material Extrusion – In its most common form, a polymer filament is drawn through a heated nozzle, melted, and then deposited layer by layer forming the three-dimensional part geometry. It is common for the nozzle to move sideways in the “X” and “Y” axis, and the build platen to move up/down in the “Z” axis. Extremely large versions of this printer type pump a stiff concrete mortar material to a programmable, three-axis, nozzle and print entire homes on the designated build site.
  2. Sheet Lamination – Printers in this category use a flat feedstock material in the form of rolls, ribbons, sheets, or strips. A system utilizing metallic materials bonds layers together via ultrasonic energy. Another system uses standard copy machine paper, ink, and glue to create full-color, 3D objects in stunning detail.
  3. Directed Energy Deposition (DED) – This process can be used with polymers and ceramics as well, but it is often used with a metallic feedstock that is introduced to the machine in powder or wire form. DED systems generally consist of a spray nozzle mounted on a programmable, multi-axis, robotic arm that directs a stream of melted material onto the targeted build surface where it solidifies. The added energy required to liquefy the metal can be introduced into the system in the form of high electrical current, laser or electron beam. One unique system uses gas jets to accelerate metal particles to supersonic speed. Upon the particle’s collision with the stationary target, the sheer kinetic energy causes the metal to deform and stick to the substrate.
  4. Keller Technology StereolithographyStereolithography (SLA) – This category of machine uses a vat of liquid photopolymer resin as its material feedstock. A computer-controlled, ultraviolet light projection system exposes the photopolymer to an “image” of each individual layer of the object being produced. As each layer is cured, the motorized build platen repositions the “Z” axis of the part within the vat of uncured resin. As the process uses liquid to form objects, there is no structural support from the material during the build so support structures will often need to be added. The process of photopolymerization is relatively fast compared to the other additive manufacturing processes; therefore, this type of printer is already being used by large global companies to produce consumer products such as the soles of running shoes and protective cases for cell phones.
  5. Material Jetting – This process creates objects in a similar method to a two dimensional ink jet printer. Liquid feedstock material is jetted via a nozzle(s) into the build envelope using either a thermal or piezoelectric dispensing method. The material solidifies by cooling, evaporation or exposure to UV light. Capable of nanoscale precision, machines of this type vary in complexity and in their method of guiding the droplets of material. This process allows for multiple materials within the same part and also the printing of biologic materials in controlled environments.
  6. Industrial Laser Additive ManufacturingPowder Bed Fusion – This process includes Direct Metal Laser Sintering (DMLS), Electron Beam Melting (EBM), Selective Heat Sintering (SHS), Selective Laser Melting (SLM) and Selective Laser Sintering (SLS). All of these methods use either a laser or electron beam to fuse particles together and require the spreading of a powder feedstock material over previous layers. A roller or a blade sweeps a uniform layer of material, from an adjacent hopper of powder, over the part. The programmable beam of energy sinters the powder, layer by layer. On the other hand, SHS differs from the other processes because it uses a heated thermal print head to fuse the granules of powder together.
  7. Binder Jetting– This process is similar to the Powder Bed Fusion process in many respects, however, it uses two materials; a powder-based feedstock material and a liquid binder. The binder is an adhesive and provides a temporary bond between the powder particles and also the powder layers. A programmable nozzle moves horizontally along the “X” and “Y” axes of the build area and deposits a precise amount of the binder in the desired locations. After printing of the part geometry is completed, the part is sintered in a furnace which burns away the binder and fuses the powder particles together. The post-process fusing does shrink the part; however, this size reduction is consistent and predictable and is compensated for during planning.

AM is changing the way consumer products are designed and component parts are being produced. With newer and more powerful software becoming available and as evolving 3D printing processes being invented, it’s only a matter of time before every consumer benefits from this new manufacturing technology. Keller Technology Corporation is excited to see what the future has in store for the factories of the future. Contact us to learn more about possible solutions to your most challenging manufacturing problems.

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