Precision Machining is a process to remove material from a workpiece during holding close tolerance finishes. The precision machine has many types, including milling, turning and electrical discharge machining. A precision machine today is generally controlled using a Computer Numerical Controls (CNC), which relies on 3D CAD files as guide for the machining operation and the 2D engineering drawings for tolerances.
A Horizontal Machining Center (HMC) is a machining center with its spindle in a horizontal orientation. This machining center configuration favors uninterrupted production work. One reason for this is that the horizontal orientation encourages chips to fall away, so they don’t have to be cleared from the table.
Electrical Discharge Machining (EDM) is a manufacturing process whereby a desired shape is obtained using electrical discharges (sparks). Material is removed from the work piece by a series of rapidly recurring current discharges between two electrodes, separated by a dielectric liquid and subject to an electric voltage. One of the electrodes is called the tool-electrode, or simply the “tool” or “electrode,” while the other is called the workpiece-electrode, or “work piece.” The process depends upon the tool and work piece not making actual contact.
Surface grinding is manufacturing process used to produce a smooth finish on flat surfaces. It is a widely used abrasive machining process in which a spinning wheel covered in rough particles (grinding wheel) cuts chips of metallic or nonmetallic substance from a workpiece, making a face of it flat or smooth.
In the simplest terms, 5-axis machining involves using a CNC to move a part or cutting tool along five different axes simultaneously. This enables the machining of very complex parts, which is why 5-axis is especially popular for aerospace applications.
Tool management is needed in metalworking so that the information regarding the tools on hand can be uniformly organized and integrated. The information is stored in a database and is registered and applied using tool management. Tool data management consists of specific data fields, graphics and parameters that are essential in production, as opposed to managing general production equipment.
A jig is a type of custom-made tool used to control the location and/or motion of parts or other tools. A jig’s primary purpose is to provide repeatability, accuracy, and interchangeability in the manufacturing of products. A jig is often confused with a fixture; a fixture holds the work in a fixed location. A device that does both functions (holding the work and guiding a tool) is called a jig.
Cold finished steel is essentially hot rolled steel that has further processing. Cold finished steel is typically produced as turned bars or cold drawn bars. Cold drawing hot rolled bars is accomplished by pulling (drawing) a bar through a die which is smaller than the incoming hot rolled size. The cold working process improves the dimensional tolerances of the bar, the straightness, the surface appearance as well as enhancing the physical properties of the steel.
Porcelain enameling is the application of glass-like coatings to metals such as steel, cast iron, aluminum, or copper. The purpose of the coating is to improve resistance to chemicals, abrasion and water and to improve thermal stability, electrical resistance and appearance.
Threading is the process of creating a screw thread. More screw threads are produced each year than any other machine element. There are many methods of generating threads, including subtractive methods (many kinds of thread cutting and grinding, as detailed below), deformative or transformative methods (rolling and forming; molding and casting), additive methods (such as 3D printing), or combinations thereof.
Sand casting, also known as sand molded casting, is a metal casting process characterized by using sand as the mold material. The term “sand casting” can also refer to an object produced via the sand-casting process. Sand castings are produced in specialized factories called foundries. Over 60% of all metal castings are produced via sand casting process. Molds made of sand are relatively cheap, and sufficiently refractory even for steel foundry use. In addition to the sand, a suitable bonding agent (usually clay) is mixed or occurs with the sand. The mixture is moistened, typically with water, but sometimes with other substances, to develop the strength and plasticity of the clay and to make the aggregate suitable for molding. The sand is typically contained in a system of frames or mold boxes known as a flask. The mold cavities and gate system are created by compacting the sand around models called patterns, by carving directly into the sand, or by 3D printing.
When speaking of cast bronze products, there are numerous methods of casting currently in use. These are sand casting, centrifugal casting, and continuous casting. The superior qualities of continuous casting are achieved by feeding molten metal through a furnace to an inert cast protected casting furnace. Any dirt, dross, or gasses present rise to the top of the melt and are left behind in the casting process. Shrink at the water-cooled graphite die is prevented by continuous feeding of molten metal. With precise temperature control, the rollers withdraw the cast bronze at a carefully controlled rate. This determines the grain structure and metallurgical properties. The continuous casting process prevents shrinkage cavities, porosity, or dirt that would otherwise introduce imperfections into the metal. This sophisticated and tightly controlled process yields a bronze bar, tube, or plate with the following advantages.
A Coordinate Measuring Machine (CMM) is a device that measures the geometry of physical objects by sensing discrete points on the surface of the object with a probe. Various types of probes are used in CMMs, including mechanical, optical, laser, and white light. Depending on the machine, the probe position may be manually controlled by an operator or it may be computer controlled. CMMs typically specify a probe’s position in terms of its displacement from a reference position in a three-dimensional Cartesian coordinate system. In addition to moving the probe along the X, Y, and Z axes, many machines also allow the probe angle to be controlled to allow measurement of surfaces that would otherwise be unreachable.
Dimensional inspection, also called dimensional metrology, assesses the geometric characteristics of machined parts and products to verify their compliance with design specifications. Dimensional inspection services ensure the accuracy of the product features that can affect reliability and functionality. Inspection is often a critical step during product development or following production.
Rolled ring forging is a process that uses two curved dies to deform the metal. Normally, the dies are two opposing rollers. This method produces forged products with a final shape that is similar to the dies. The rolled ring process is largely used due to its many benefits including a long lifespan, high productivity, low cost, and quality finishes, which are used in producing ring gears, mechanical seals, sleeves, and flanges.
Closed die forging is a process that shapes a metal part by forcing it into the contours of a die. This process gets the name “closed-die” because the material is confined between an upper and lower die. The closed-die process requires a significant amount of force, where it is often used to produce near net products, such as crack shafts, cam shafts, or suspension lugs.
Open die forging is a process that plastically deforms the metal with a series of compressive forces. It is carried out between two flat dies or simple shapes. Usually, the dies do not completely enclose the material, which is why this process is called “open-die.” The open die forging method is used mostly for large objects with smaller quantities in the marine industry.
Investment casting is an ancient manufacturing process used for metals that are difficult to be machined or fabricated using conventional methods. Parts that could be produced using investment casting include turbine blades or components of airplane that are subjected to high temperatures while in operation. This process provides an excellent dimensional accuracy and surface finish.
The pattern is made of wax or other substance that is melted, leaving behind a cavity which the mold is filled with the material of the part being produced.
In this process metal is forced into the mold at a high pressure that ensures production of identical parts, a better surface finish, and an increased dimensional accuracy. Some parts produced by die casting even do not require post-casting machining or may require only a light machining to achieve the desired dimensions. Defects of porosity are found more often in large castings because of entrapped air and the solidification of melt before it reaches the boundaries of the cavity. Parts with a uniform wall-thickness can be more accurately produced by die casting. Additionally, Die-casting molds are expensive since these are made from hardened steel or aluminum and because a longer time duration is required for their production.
Gear Hobbing is a machining process for gear cutting, cutting splines, and cutting sprockets on a CNC hobbing machine, which is a special type of milling machine. The teeth or splines are progressively cut into the workpiece by a series of cuts made by a cutting tool called a hob. Compared to other gear forming processes it is relatively inexpensive but still quite accurate, thus it is used for a broad range of parts and quantities. It is the most widely used gear cutting process for creating spur and helical gears and more gears are cut by hobbing than any other process as it is relatively quick and inexpensive.
Additive Manufacturing (AM) is a term to describe set of technologies that create 3D objects by adding layer-by-layer of material. All of the listed manufacturing operations presented in this report are considered subtractive manufacturing.
In additive manufacturing, materials can vary from technology to technology, but there are some common features for all Addictive Manufacturing, such as, usage of computer together with special 3D modeling software. First thing to start this process is to create 3D CAD file. Then AM device reads data from CAD file and builds a structure layer-by-layer from printing material, which can be plastic, liquid, powder filaments, or even sheet of paper. The following are the different types of popular 3D printing technologies:
• Stereolithography (SLA)
• Digital Light Processing (DLP)
• Fused deposition modeling (FDM)
• Selective Laser Sintering (SLS)
• Selective laser melting (SLM)
• Electronic Beam Melting (EBM)
• Laminated object manufacturing (LOM)
Post manufacturing processes include plating, coating, and heat treatment. For example, heat treatment is a group of industrial and metalworking processes used to alter the physical, and sometimes chemical, properties of a material after fabrication. Heat treatment involves the use of heating or chilling, normally to extreme temperatures, to achieve a desired result such as hardening or softening of a material to help achieve the design intent of the part while in operation. Further, heat treatment techniques include annealing, case hardening, precipitation strengthening, tempering, normalizing and quenching. It is noteworthy that while the term heat treatment applies only to processes where the heating and cooling are done for the specific purpose of altering properties intentionally, heating and cooling often occur incidentally during other manufacturing processes such as hot forming or welding. Although some of these services exist at local manufacturing establishments, there is room for specialized new entities to enter this realm.
Digital manufacturing is an integrated approach to manufacturing that is centered around a digital representation of parts. Overall, digital manufacturing can be seen as sharing the same goals as computer-integrated manufacturing (CIM), flexible manufacturing, lean manufacturing, and design for manufacturability (DFM). The main difference is that digital manufacturing evolved for use in the computerized world. Manufacturing engineers use 3D modeling software to design the parts for industrial applications by relying on a comprehensive digital representation of the parts themselves, where they would have a digital archive of:
• Optimization of a parts manufacturing process. This can be done by modifying and/or creating procedures within a virtual and controlled environment.
• Digital manufacturing allows for testing & evaluating the part & how it would experience loads once manufactured before investing time and money into creating the physical part.
• Enables Cloud based Design & Manufacturing, which is a practical implementation of Just-in-Time manufacturing, pull vs. push inventory restocking of parts/equipment, and on-demand manufacturing or lean manufacturing.
• Facilitates Competitive Bidding of parts & equipment from suppliers because of the availability of technical data for manufacturing.
• Enables the use of CNC or Additive Manufacturing (3D printing) using a verity of material options (metallic or plastic) to help save time & cost. Digital Additive manufacturing is highly automated which means less man-hours & machine utilization, and therefore reduced cost. By incorporating model data from digitized sources by means of reverse engineering, products can be produced quickly, efficiently, and cheaply!
• Enables Rapid Manufacturing, which uses digital models to rapidly produce a product that can be complicated in shape and heterogeneous in material composition either using conventional or additive manufacturing. Rapid manufacturing utilizes not only the digital information process, but also the digital physical process. Digital information governs the physical process of adding material layer by layer until the product is complete. Both the information and physical processes are necessary for rapid manufacturing to be flexible in design, cheap, and efficient!
Digital manufacturing is just one of many ways that leverages the use of technology & digital information to make our lives easier, more flexible, and less prone to import/export threats!
With digital manufacturing, Dartec can provide you reduced costs, increased efficiencies and rapid manufacturing