The process sometimes utilized when multiple layers of Fluoropolymer coatings are to be applied. The first coat is incompletely cured. The second coat is applied and both are fully cured together. (See Flashing).

The time/temperature relationship that the part must see which is required to cure that specific coating so it can develop its specified properties.

Alloy casting process commonly used to produce high volumes of intricate parts. The process sometimes entraps small bubbles in the metal that can result in "blow holes" when the coating is cured.

By designing a workflow like this in your shop, you can spend less time worrying about the precision of printed parts by adding in subtractive operations to keep material costs low, create less waste, and keep parts in tight tolerances for precision machining excellence.

Quality of thermosetting plastic resins in which polymer chains combine during the curing process. In general, the greater the crosslinking, the tougher and more chemically resistant the coating.

Is an elastomer created by the chemical reaction between an isocyanate and an amine. Attributes include abrasion protection, corrosion protection, chemical resistance, noise reduction, slip/grip, and additional strength qualities (to some substrates).

Process of shaping parts after a coating has been applied and cured, a technique commonly used with stamped, blanked or spun parts.

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"TEFLON® is a registered trademark of DuPont." For more information, see Merriam-Webster online dictionary (www.m-w.com/dictionary), Concise Encyclopedia: Teflon: Trademark for a polymer of tetrafluoroethylene fluorocarbon (polytetrafluoroethylene [PTFE]). Function: trademark --used for synthetic fluorine-coating resins used especially for molding articles and for nonstick coatings. Learn more about "Teflon" and related topics at Britannica.com. A closely related fluorocarbon polymer, fluorinated ethylene-propylene (FEP), has properties and applications similar to those of Teflon®. (See PTFE, PFA, FEP, ETFE, Dry lubricants).

High-molecular weight thermoplastic of vinylidene fluoride with excellent strength, wear resistance and creep resistance.

The term Alternative Energy has many meanings in today’s environment. The most common: A form of creating energy that does not cause carbon dioxide emissions. For example, Fuel cells, Wind Generators, and Hydrogen Cells are the most talked about. Alternative energy coatings are used to stop corrosion caused by chemical reactions.

Overall, in 2021 we are still early on in this new revolution of hybrid machining and advanced design methods, but it is important to understand the role that adding a CNC machine could have in your additive-focused shop, and vice versa. By combining additive and subtractive together, shops can mitigate the cons of each method and take full advantage of the benefits of having both options available on the shop floor.

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Is commonly used in the coating industry, is equivalent to 1/25th of a mil, i.e., 25 microns are equivalent to one mil of coating thickness, or one mil of coating thickness is equivalent to 25 microns.

The ability of a coating material to maintain uniform physical and chemical properties while in storage over extended periods of time. Most coatings have a shelf life, some even have a shelf life after they have been applied – as in the case of rubber to metal adhesives.

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A resin or plastic, usually thermosetting, made by condensation of a phenol with an aldehyde and used for molding, insulating, coatings and adhesives.

A thermoplastic member of the Fluoropolymer family. FEP has excellent nonstick and nonwetting properties, in addition to low friction. These coatings provide excellent chemical resistance. Maximum use temperature is 205° C/400° F.

A process where the temperature of PTFE is raised to the point where PTFE particles soften and form a bond with each other.

Finely divided particles of organic polymers, pigments, and additives. (Powder coating is not a common process at DECC, except in the case of unique masking requirements, or requirements for Ryton Powder).

Excellent write-up! Kudos to you guys! Your point is absolutely right that 3D printing of metal parts is becoming more common, but subtractive manufacturing is an important part of manufacturing precision additive parts.

A value determined by measuring the relative hardness of a coating based on the ability of the coating to resist penetration and gouging by pencil lead of varying hardness. The order of pencils from softest to hardest is 4B, 3B, 2B, B, HB, F, H, 2H, 3H, 4H, 5H, 6H, 7H, and 8H. The hardness rating of the coating is equal to the first pencil which does not penetrate and gouge the coating.

As hybrid manufacturing workflows become more popular, so do new hybrid manufacturing machines. These hybrid machines are all-in-one machines where both additive and subtractive manufacturing can be performed in a single setup. Many of these machines offer metal 3D printing as well as multi-axis machining capabilities, ready for even the most complex parts thrown their way. With a bit of customization, large-scale 3D printing machines or CNC mills can be retrofit to allow for hybrid manufacturing with add-ons from companies like Hybrid Manufacuring Technologies.

Coating technique similar to siphon spraying, except that the coating is delivered from a pressurized pot to the spray nozzle under positive pressure. Generally used for high-volume production.

There is no doubt that the additive manufacturing space will continue to develop and grow in the coming years, but will it render subtractive manufacturing methods like CNC Machining obsolete? Absolutely not. In fact, precision CNC machining is likely more important to the additive manufacturing process than you may think, as a new process called “hybrid manufacturing” is quickly taking hold in the industry.

Surface pretreatment used on ferrous or aluminum parts that provides a very thin crystalline film that enhances both corrosion resistance and adhesion. (A microcrystalline zinc phosphate process “250 milligrams +/- 50 per square inch” is used at Decc).

With recent advancements in 3D printing capabilities, it is becoming easier for manufacturers to use additive manufacturing to create parts from a wide variety of materials, including polymers like ABS, TPE, and PLA as well as carbon fiber composites, nylon, and polycarbonates. Even pricey metals like Titanium, Stainless Steel, and Inconel are becoming increasingly common in the world of additive manufacturing as well.

As parts come off the printer, they can be quickly moved into a CNC machine with a program designed for part completion. The CNC machine will be able to get 3D printed parts down to the tight tolerances required by many industries and reach the desired surface finish. Advanced finishing tools and long reach, tapered tools from brands like Harvey Tool can easily machine the tight geometries of 3D printed parts, while extremely sharp diamond-coated tooling and material-specific tools designed for plastics and composites can work to create a beautiful, in-tolerance finished part regardless of the material.

Plastic resins that have high-performance properties such as high-temperature stability, hot hardness, abrasion resistance and corrosion resistance.

A characteristic of liquid and powder coatings in electrostatic application to adhere to areas of the substrate not in direct line of sight of the delivery system endpoint.

Process of metal decomposition (oxidation) in which metal ions are united with oxygen to form metal oxides. Fluoropolymer coatings provide excellent barriers against most corrosives.

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The removal of a coating by elevating the temperature of the part(s) above the degradation point of the coating and holding it until the coating carbonizes (See Burn Off).

Cleaning process that employs a high pH solution (caustic). A good choice for parts with a little buildup of contaminants.

Warming of parts prior to application of a coating, recommended when adhesion is critical and when parts are being coated in humid atmospheres. In some cases, this technique can be used to achieve higher-than-normal film builds.

Federal, state or local laws, statutes or regulations of which their intent is to protect human health and the environment. Examples are the Clean Air Act (CAA), and the regulations which govern the storage, transportation, and disposal of hazardous waste, the Resource Conservation and Recovery Act (RCRA).

A heat treatment that alters the microstructure of a material causing changes in properties such as strength and hardness.

Is a copolymer of Ethylene and Tetrafluoroethylene. ETFE is a thermoplastic member of the Fluoropolymer family. ETFE is noted for exceptional chemical resistance, toughness and abrasion resistance. Although not fully fluorinated, ETFE has excellent chemical resistance and can operate continuously at 150° C/300° F. This resin is the toughest of the Fluoropolymers and can be applied to film builds up to 1,000 micrometers (40 mil) to provide a highly durable finish.

Before implementing a hybrid manufacturing approach, it is important to understand the pros and cons of each method. Here is a quick breakdown of both additive and subtractive manufacturing, and the benefits and drawbacks of each.

Material that can support the flow of electrical current. Fluoropolymer coatings are normally insulators but can be modified with certain fillers and pigments to make them conductive.

Conditioning the substrate before coating through grit blast, phosphate, etc. May include the removal of a coating (See Burn Off).

A deposition method of spraying coating a group of small parts as they tumble in front of a spray gun. This is an economical method of coating small bulk parts. Due to the nature of this application method, some parts will exhibit material build-up, tangling, sticking or scuff-marks.

A substance added to a formulation in relatively small amounts to impart or improve desirable properties or suppress undesirable properties.

Most common technique for applying coatings, also known as "conventional air spray." The coating is drawn from a reservoir into an atomizing air nozzle and propelled toward the surface to be coated.

Thermoplastic member of Fluoropolymer family of engineering plastics. The additional benefits of higher continuous use temperature (260° C/500° F), film thicknesses up to 1,000 micrometers (40 mil) and greater toughness than PTFE or FEP. This combination of properties makes PFA an excellent choice for a wide variety of uses especially those involving chemical resistance. PFA is characterized by excellent release, low friction, and toughness.

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The term generally used to describe unwanted vibrations in an automobile. NVH is a generic term/acronym that covers the branch of engineering relating to vehicle refinement in terms of noise (acoustic) and vibration experienced by the occupants when the vehicle is in service. The term is used mainly in connection with road vehicles, but exactly the same techniques are used in air and rail transport to improve refinement.

A method of removing a coating. Temperature is elevated above the degradation point of the coating and held there until the coating breaks down. Also, a method used to clean a metal surface. (See surface preparation).

The ability of additive machines to literally “add-on” to a part can also make for a cheaper approach to part design. Instead of using expensive materials like Inconel or Titanium to machine an entire part, portions of the part that do not require extreme heat resistance could be machined out of cheaper steel, while the heat resistant portions using expensive materials can be added later through additive methods.

This is the build-up of coating on a part. Often a concern on a mechanical fit. To compensate for coating stack-up, parts often have to be machined down to allow for the coating build-up.

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As manufacturing and design techniques get progressively “smarter” with CAM/CAD programs offering generative design and artificial intelligence, these hybrid machines could become a new standard in high-end machine shops working in advanced manufacturing industries like aerospace, medical, defense, and the mold, tool & die market.

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Processes for cleaning and conditioning a substrate to be coated. Next to the choice of coating, this may be the most important factor in the use of high-performance coatings.

If your shop is focused completely on subtractive manufacturing methods, you are probably thinking that there is no need for an additive option in your shop. Can’t a CNC machine create everything a 3D printer can, and in less time? Not necessarily. Again, by using the two methods together and taking a hybrid approach, you may be able to lower your manufacturing and material costs.

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Looking at the chart above, you will notice that one of the key differences between additive manufacturing and subtractive manufacturing is the surface finish and tolerances that can be achieved with each method. This is where a hybrid approach to additive manufacturing can be extremely beneficial.

A thermoplastic member of the Fluoropolymer family of plastics. It is a two-coat system (primer/topcoat). PTFE has an extremely low coefficient of friction, good abrasion resistance, good chemical resistance, and the highest operating temperatures of the Fluoropolymers (290° C/550° F).

A brief sub cure (at lower temperatures than the final cure) to drive off solvents or carriers prior to full cure. This helps prevent bubbling. (See Partial Cure).

Coating application technique in which small parts are placed in a basket that is lowered into a coating bath then raised and spun to remove excess coating. An economical system for coating high volumes of small parts. This is not an application method that DECC currently performs. For Decc’s alternative economical system for coating high volumes of small parts. (See Tumble Coat).

Solid materials such as PTFE, PFA, FEP, ETFE, Moly Disulfide (MoS2) and graphite that have low coefficients of friction.

Repulsion of charged particles because of the part's concave shape. Charges build at the entry area, preventing penetration into the cavity.

A family of engineering plastics containing fluorine, characterized by high thermal stability, almost universal chemical resistance and low friction.

The process of surface cleaning and roughening that provides a mechanical "tooth" to aid coating adhesion. Media include aluminum oxide, even crushed walnut shells. The medium must be chosen to match the substrate and the foreign material on the substrate to be removed. (We utilize the aluminum oxide media here at DECC) (See Aluminum oxide).

Creating a hard oxide surface on aluminum parts via an electrolytic process. Unsealed anodized surfaces have a porosity that makes them excellent substrates for coatings. This is not an application method that DECC currently performs.

For example, you could machine the bulk of a part with typical subtractive machines, which would likely take a very long time using additive methods. Then you can go back to that part with a 3D printer to add intricate features to the part that may take complex programming and hours of planning on a subtractive machine. An impeller is a great example, where the bulk of that part can be machined, but the tricky fins and blades could be printed onto the part, and then finished back on the CNC machine.

A flexible resin, usually thermosetting, made by polymerization of an epoxide and used chiefly in coatings and adhesives.

A deposition method of spraying and charging a coating so that it is deposited on a substrate (usually grounded). A spray application process in which the coating and part to be coated are oppositely charged (referred to as electrostatic coating); process provides excellent "wrap" of coating around the part, even on sides opposite the spray gun. (See Faraday Cage Effect).

One thousandth (0.001) of an inch (25.4 microns). This is the most common non-metric measurement of coating thickness. (This is the measurement system that is used at DECC).

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A resin designed to undergo an irreversible chemical and physical change when undergoing a heat-cure schedule, i.e., A plastic resin that crosslinks during cure so that it does not soften when reheated.

Any surface to be coated. This can include metals such as steel, cast iron, bronze, brass, aluminum, stainless steel, chromium and, with special precautions, nickel. Paper, most plastics, wood, leather, fabrics, and glass can also be coated.