Diamond-drag engraving, burnishing adaptors, rotary cutters, micrometer dials, cutting angles, speeds and feeds. For someone new to the engraving business, or someone only familiar with laser engraving, those words might as well be written in a foreign language. In reality, however, they represent the very core of our industry—rotary engraving.
Actually, the term “rotary engraving” is a misnomer. It has historically been called “mechanical engraving” because the cut is done mechanically using a cutter. However, since the advent of laser engraving a lot of users have adopted the term “rotary engraving” to describe what we do with a rotating cutter or a nonrotating diamond graver.
Long before lasers came on the scene, rotary engravers were making their mark on mainstream products like trophies, plaques, signage, giftware and jewelry, not to mention items off the beaten path like bowling balls, skis and computer key caps. Since laser engraving was introduced to our industry, some would say that rotary engraving has slipped into the background or even gone the way of the dinosaur. After all, who wants to deal with cutters and depthing and setting spindle speeds when you can just put an item in a cabinet, push a few buttons and laser engrave?
While it’s true that lasers have many advantages—they’re versatile, easy to use and affordable—it’s also true that rotary engraving is still alive and well in our industry. In fact, in many cases, depending on the application, rotary engraving is by far the most preferred marking method for the job. Indeed, it’s the only practical method for many jobs!
“Are people still buying and using rotary engraving machines? Absolutely,” says Natalie Whitehouse, Marketing Coordinator for Vision Engraving Systems, Phoenix, AZ.
“This marking method is very valuable to the industry for a number of reasons. Namely, there are some jobs that just work better with a rotary engraver.”
Still, for rotary engraving novices, the idea of plunging into rotary engraving can be a little daunting because of unfamiliarity with the process. The reality is that rotary engraving is really not that difficult and it doesn’t necessarily require a great deal of skill, especially with the new machines and equipment available today. This article serves as a basic primer about rotary engraving—what it is, how it works and all of the wonderful opportunities it can present to an engraving business.
What is Rotary Engraving?
Rotary engraving is the process of using a spinning cutter in a motorized spindle to cut into material, either completely through the substrate to create cut out shapes or holes, or at a predetermined depth to create engraved grooves that form characters and graphics. Diamond drag engraving is similar to rotary engraving in that you can use the same machine but you use a diamond-tipped, nonrotating cutter to cut into the material. This method is primarily used for engraving metal.
Rotary Engraving Applications
One of rotary engraving’s best traits is that it can be used to engrave a wide range of materials, including a variety of plastics, acrylic, glass, ceramic, wood, stone and solid surface material. Unlike CO2 laser engraving systems, rotary engraving systems can also engrave on just about any type of machinable bare metal, including aluminum, brass, stainless steel (machinable grades), silver, gold, titanium and platinum.
However, if you are one of those people who want to know rotary engraving’s true claim to fame, it’s the ability to mark/engrave/personalize metal items. Using rotary engraving you can personalize just about any metal item, including off-the-shelf items you can buy anywhere. A partial list of rotary engravables would include Rolex watches, identification bracelets, metal pens, die struck medals, charms, 14K wedding rings, bridal cake knives, brass or aluminum plates, etc. If it’s uncoated metal, you can engrave it. If it’s coated, you can engrave it. Rotary engraving will work on precious metals, semi-precious metals, stainless steel, brass, pewter—you name it!
Because of the wide range of substrates that rotary machines can engrave, you have the opportunity to take your engraving skills into a variety of different markets. The awards market, of course, is a big area for rotary engravers and includes products such as trophy plates, plaque plates, corporate gifts and acrylic awards. And while lasers are also great for engraving most award products, they are not necessarily suited for many traditional engravable gift items, such as jewelry and metal products like tankards, flasks, compacts, boxes, luggage tags, etc.
“There are a lot of people who have been engraving trophies and awards as their core business and have added personalized gifts to their inventory,” says Whitehouse. “Engravers who expand into these areas often find that something like our MAX Pro (Vision’s rotary engraving machine designed for gift engraving) is perfect for them.”
Signage is another area where lasers and rotary engravers both have a foothold. However, when it comes to ADA signage, rotary engraving holds the advantage because it’s easier to create the required raised lettering and braille dots. “ADA signage is an area where we are continuing to see a lot of growth for rotary engraving,” adds Whitehouse. “You can use the rotary machine to create the letter cutouts and then switch the cutter, drill holes and place the ‘Raster’ Braille beads directly into the holes, which is something you really can’t do with a laser. Also, to strictly follow the law, you can’t really achieve a true ADA sign with Raster Braille using a laser because you can’t get the right angle of cut,” she says.
Another major market area for rotary engraving is the industrial sector. “Industrial applications, including manufacturing and machining, are a major area for rotary engraving,” says Jessica Hoffpauir-Freeman, Director of Marketing for Xenetech, Baton Rouge, LA. “Rotary engraving is excellent for permanent marking on fixtures for plants and large manufacturing facilities as well as UID barcoding.”
Laser and rotary engraving also produce different “looks,” and in many cases it’s the look of rotary engraving that customers want. “Rotary machines truly ‘engrave’ rather than ‘mark’ or ‘burn’ products,” says Jon Lawry, Sales and Marketing Communications Manager at Gravograph, Duluth, GA. “Oftentimes this is desirable for appearance and permanence.”
Whitehouse agrees. “There are a lot of things that you can do really well with a laser, such as trophy plates, acrylics and paper. And, if you want that burned-in look on wood, you’re better off with a laser. But there are other projects that are much better suited for a rotary system,” she says. “For example, if you want to do stainless steel engraving, then rotary is really the best system. Glassware is another substrate that comes out much cleaner on a rotary machine than it does with a laser.”
What Equipment is Available?
There are two general categories of rotary engraving machines: manual, also known as pantographs, and computerized. On a pantograph machine, you manually lower the cutter to the material and create engraved characters by holding down the cutter and tracing a master template with a stylus. Computerized engraving machines use software, sophisticated electronic controls and stepper motors to mechanically lower the cutter and move it along the X and Y axes to engrave. Although most of the industry has moved into computerized engraving, manual machines are still favored for certain jobs. “The manual machines are still used for simple low-quantity text engraving, such as for watches, simple awards and the like,” says Lawry. Pantograph engraving is also often considered a “foolproof” alternative when it comes to engraving valuable items or family heirlooms.
There are a wide variety of computerized engraving machines available to suit almost any application. They include small countertop systems that take up less than one square foot, systems capable of engraving rings, gifts and cylindrical objects and large flat table systems that can engrave a large quantity of badges or signs at one time. All of the major machine manufacturers, including Gravograph, Vision Engraving Systems and Xenetech, offer a complete line of computerized engraving machines in a variety of sizes and configurations. The main differences between these systems are cost, size and capabilities.
Generally speaking, smaller rotary machines have an engraving area of around 4" x 3" to 9" x 12" and range in cost from $2,000-$8,000. These machines are designed for engraving items such as jewelry, award plates, small gifts, pens, single badges and small industrial plates and tags. Mid-sized engraving systems have larger engraving areas, e.g. in the range of 12" x 12" to 16" x 12", and have a price tag of around $10,000-$20,000. Mid-sized machines can do everything a smaller system can, plus larger gift items, signs and industrial parts.
Large rotary engraving systems feature a movable “bridge” that travels across the table allowing you to engrave very large items or multiple items at one time, such as a batch of badges, signs or nameplates. These machines can have a working range of 24" x 48" or larger, depending on the manufacturer, with prices ranging from $12,000-$30,000. “Obviously there’s a cost difference. Essentially it depends on what size project an engraver wants to do,” Whitehouse states.
What About Software?
A major link to successful computerized engraving lies in the software. A good software package allows you to quickly and easily create text, graphics and even photographs that can be engraved on your computerized system. Most engraving machine manufacturers offer their own proprietary software, either as an option or bundled with their engraving machines, and some third-party software developers, such as CADlink Technology Corporation, Ottawa, Ont., Canada, offer engraving-specific programs. These packages are custom built to drive engraving machines, which makes communication between the software and the table exceptionally smooth. “There are many efficiencies that can be taken advantage of in buying engraving-specific software that are over and above off-the-shelf graphics applications,” says Tim Benner, Engraving and Routing Sales Manager for CADlink.
CADlink and all of the major machine manufacturers offer engraving-specific programs to make your job easier. These software packages are typically sold in different versions, ranging from basic to more advanced, so you can select a program based on your applications.
One of the major advantages of engraving software is that it gives you access to a wide variety of engraving-specific applications. For example, many engravers regularly use a feature known as auto layout for standard jobs. Auto layout lets you automatically create attractive award, gift and sign layouts based on basic information that you input, such as type size and line spacing. Another popular engraving feature is matrix engraving, also known as multiple plate engraving, which is the software’s ability to consecutively engrave a series of small plates onto one larger piece of material in a step-and-repeat fashion. A similar feature, called batch engraving, involves consecutively engraving the same layout but different text on a series of precut plates. Both of these are time-saving features for jobs like badges, signs and nameplates.
As noted earlier, today’s machines are not nearly as complicated as they were many years ago, and much of the credit for that goes to improved software. For example, some software now allows you to essentially define the layout directly on the item to be engraved using a red laser pointer. Say, for example, you need to engrave a belt buckle that has a small rectangular area in the lower right corner designated for engraving. You can manually jog your engraving machine’s spindle to each of the four corners of the rectangle and register those points in the software to define the engravable area. The software will then display the rectangle (engravable area) on your computer screen where you can input text/graphics. When the job is sent, the engraving machine knows exactly where on the buckle to start engraving. This feature is extremely handy for engraving jewelry and other small engravables that aren’t necessarily symmetrical. It is also a great option for engravers who prefer a visual approach to engraving as opposed to a mathematical one.
Another trend in recent years is the ability to generate and engrave just about any kind of graphic image, including logos and photographs. This can be accomplished in a variety of ways, including scanning and importing graphics from other programs such as CorelDRAW, and then converting them into a format suitable for engraving. Most of today’s software also provides a variety of design capabilities for creating your own graphic images.
There are also many features for specific applications, such as creating ADA signage, including braille and raised lettering, engraving seals and generating dials for industrial control panels.
Fonts Are Included
Another advantage of computerized engraving software is that most programs come stocked with a variety of fonts that are true “engraving fonts.” Many graphical fonts, such as those found in CorelDRAW, are bitmap fonts or, in other words, they are made up of dots. This is fine for laser engraving or printing on an inkjet printer, but these fonts are not readily engravable because rotary engraving is a vector-only process. Engraving fonts, also called “stick” or “stroke” fonts, are made up of vectors (lines and arcs) that can be engraved with an engraving cutter. There are a variety of generic engraving fonts available that have a fixed number of lines that can be engraved.
Many programs are also compatible with TrueType fonts (of which there are thousands available), which may or may not be included with the software. Depending on the font and the look desired, TrueType fonts might need to be converted into stroke fonts for engraving, another feature of many programs.
Rotary Engraving Basics
With the proper equipment and software, all you need are some basic accessories to get started. Engraving cutters are the tools used to get the job done. Cutters are made from different materials and in different configurations depending on the material, application and overall look you want to achieve.
Spindles—The spindle is the device that holds the cutter in place during engraving. Most of the engraving machines used in this industry feature “top-loading” spindles, meaning that a cutter is inserted into the top of the spindle and (usually) is secured with a threaded “cutter knob.” Cutters for top-loading spindles are available in various shank sizes, including 1/8", 11/64", 1/4", 4mm and 6mm diameters as well as various lengths to fit the spindle. The advantage of top-loading spindles is that you can quickly and easily load and unload cutters and preset the cutters to the desired engraving depth at the onset of the job.
Collet spindles are also available, particularly on larger, industrial type machines. This type of spindle features a collet (similar to a drill chuck) that tightens around either a bottom- or top-loading cutter to hold it in place. This type of spindle is more rigid and precise, but involves more time to change cutters.
Diamond Gravers—A diamond graver consists of a small, conical shaped diamond set into the tip of a metal cutter shank. These non-rotating cutters can be inserted into a rotary spindle (and used with the spindle motor turned off) or used with a spindle designed specifically for non-rotating diamond engraving. You can also use a diamond-drag adaptor, which is essentially a small diamond cutter that attaches to the bottom of a rotary spindle.
A diamond cutter (graver) “drags” across the material surface (hence the name diamond-drag engraving) to create a shallow, fine-line cut with a bright, polished finish. This type of cutter is used to engrave into metal, such as brass, aluminum and pewter gift items, trophy and plaque plates, jewelry, etc. Diamond gravers are available with various tip angles. A 120-130 degree angle is used for general purpose engraving, a 90 degree angle cuts deeper and is well-suited for hard metals or epoxy coatings (coated pens, for example) and a broader angle, e.g. 140 degrees, makes a shallow, wide cut that works well on soft metals like pewter or gold.
Rotating Cutters—Rotating cutters can be manufactured from “high speed steel” or tungsten carbide. Often referred to simply as “carbide cutters,” today’s tungsten carbide cutters are usually made from high performance “micrograin” carbides. These are generally more popular for engraving applications because of their toughness and durability. The cutters used for the widest range of engraving applications have a conical shape with a half-round configuration, which means that the cutter is split in half and ground with a single, angled cutting edge. Quarter-round cutters are also available for special applications, such as engraving hard metals.
Conical cutters are ground with a fine, sharp tip; the size of the tip determines the width of the cut. Cutters are also available with different clearance angles, depending on the material being engraved. Softer materials, for instance, typically require larger clearance angles in order to let the material chips escape during engraving. You can also purchase or grind cutters with different cutting angles for different applications. For example, the standard cutting angle is 30 degrees, but you might choose a cutter with a 90 degree included angle to create a deep V-groove for a dramatic effect in a material like acrylic.
When used to engrave into materials like plastic, metal, wood, solid surface material, acrylic, etc., a conical cutter produces a V-shaped cut with a flat bottom. When used to cut out shapes, e.g. cutting name badges out of plastic engraving stock, these cutters leave an attractive beveled edge.
The other common type of rotary cutter is a parallel cutter. Instead of a conical shape, a parallel cutter has a straight cutting edge that is parallel to the cutter’s axis of rotation. When used to engrave, this type of cutter produces cuts with straight walls and a flat bottom. When used to cut completely through the material, the result is a groove with straight side edges, as opposed to angled edges, an effect that is particularly desired for applications such as control panel engraving where the panel needs to fit over dials, knobs and keys.
Burnishing Cutters—A burnishing cutter is a rotating cutter with a multi-faceted tip. These cutters are used in conjunction with a burnishing adaptor, a spring-loaded mechanism that fits on top of the cutter and allows it to “float” across the material surface. “Burnishing” essentially involves skimming away the top lacquered surface of the material and just a tiny amount of the base metal.
Burnishing tools are wider than a diamond graver and are available in a variety of tip sizes, just like traditional rotary engraving cutters. One of the advantages of burnishing is it’s very fast, and you can use very simple single-stroke fonts while still achieving a bold, wide cut by using a wide-tipped cutter.
Carbide burnishers are typically used on coated, colored or marbled brass, aluminum and steel. For example, on lacquer-coated metal, the cutter removes the lacquer coating, exposing the bright, shiny metal underneath. Diamond-tipped burnishers can be used for aluminum, steel, silver, titanium and pewter, but they’re also an excellent tool for rotary engraving glass. As with other cutters, various tip sizes are available and the width of the tip determines the width of the cut. These tools produce a smooth, clean finish and can also result in shorter engraving times, e.g. when engraving large characters.
Specialty Cutters—There is also a wide variety of specialty cutters available designed for certain applications. For instance, spiral flute cutters (“end mills”) have spiral shaped cutting edges, similar to a drill bit. These are used for drilling and engraving or milling hard materials, such as stainless steel. There are also special cutters available for certain jobs, such as engraving ADA Braille signage, eyeglasses, bowling balls, stencils and plastic pens.
Depth Noses—When diamond engraving, the depth of cut is solely determined by the pressure the cutter exerts against the material, which is typically controlled with a spring tension adjustment on the spindle. When rotary engraving, however, the primary method for regulating how deep you cut is with a depth regulator nose.
The depth nose attaches to the bottom of a rotary spindle and, using the spindle’s micrometer dial, you can adjust how far the tip of the cutter protrudes through the nose and, thus, how deeply the cutter penetrates the material. During engraving, the nose rides along the surface of the material under tension from the spindle compression spring, providing a uniform cutting depth, even if the material isn’t perfectly flat (which it isn’t in many cases, particularly when engraving plastic).
Both plastic (nylon) and metal nose cones are available in various sizes. Plastic depth noses are only used on soft plastic materials whereas the more common metal noses are used for almost anything. Various sizes are available to accommodate different cutter sizes and for different applications. For instance, a large nose is used when making deep cuts since the cutter can extend further through the nose opening. Smaller noses have a conical shape and are well-suited for engraving on irregular or curved surfaces because the smaller size conforms better to the irregular surface.
A vacuum “foot” or adaptor is also an option. A vacuum adaptor consists of a nose cone that is attached to a vacuum chip removal system that removes material chips during engraving. This is useful for keeping the work area clean, e.g. when engraving plastic or making deep cuts. In some cases, depth noses are not used, mostly if there is a risk of scratching the material surface, e.g. deep engraving on metal.
Rotary Engraving in Your Shop
This “bird’s eye” view of rotary engraving should give you a good idea of what one of the industry’s most versatile marking methods is all about. Rotary engraving can open up avenues to a wide variety of markets that other technologies cannot, including giftware, glassware, ADA signage and much more. The equipment available today is state-of-the-art and there is a wide variety to choose from, whether you’re looking for a small gift engraving system for products like picture frames, vases and jewelry or a larger setup for jobs like architectural signage and volume production. The process itself is equally straightforward and continues to represent a major area of our industry.
“I don’t think the R&I Industry would be complete without rotary engraving, just as the music industry would not be complete without acoustical instruments,” says Gravograph’s Lawry. “There’s a ‘style’ that a rotary engraver achieves that is still desirable and practical.” Maybe it’s time to take a look at what rotary engraving can do for you and your business.
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