Engraving Cutters & Diamonds

Rotary Engraving

Description

Rotary engraving is the term used to describe engraving done with a rotating cutting tool in a motorized spindle. The tool, or cutter, cuts into the surface of the material to a predetermined depth and produces a groove of the same shape and dimension of the cutter. Rotary engraving can be performed on a wide variety of materials with plastic, brass, and aluminium being the most common in the awards industry. (click here for Anatomy of an Engraving Cutter)

Engraving Cutters 

The tools used for rotary engraving are generally referred to as “cutters.” Most engraving cutters are “half-round” tools which means the blank is split or halved on centre producing a “single-lip” tool which is one of having only one cutting edge.

The majority of the engraving machines used in the awards and engraving industry have spindles that use “top-loading” cutters. These are cutters that are inserted into the spindle from the top and are typically held in place by means of a threaded knob. This arrangement allows for easy cutter adjustments and changes. Top-loading cutters are most commonly available in 1/8”, 11/64”, 1/4”, 4mm, and 6mm shank diameters. Cutter lengths vary to accommodate machine spindles and accessories (burnishing attachments, vacuum chip removers, etc.).

Speeds and Feeds

The rate of the cutter rotation is referred to as the cutting speed, and the lateral movement is the feed rate. Each has a profound effect on the quality of the finished cut. The cutting speed is actually the measure of the distance travelled in surface feet per minute (sfpm) by the cutting edge and varies proportionally with tip size. For example, a .030” tipped cutter turning at 10,000 rpm has a speed of approximately 75 sfpm while a .060” tipped cutter rotating at the same speed generates about 150 sfpm. It is apparent then, that small cutters need to turn faster to achieve the same results as larger ones and vice versa. Cutter speed is determined primarily by the material being engraved. The following table and graph can be used as a guide.

Cutter Speed in Revolutions Per Minute

Cutter Size – Measured at Tip
Material .015″ .030″ .060″ .090″ .125″ .171″ .250″
Plastic Engravers   Stock 15,000 to 20,000rpm 12,000rpm 10,000rpm
Engravers Brass 10,000 – 15,000rpm 13,500rpm 9,500rpm 6,500rpm 5,000rpm
Free Cutting   Aluminum 15,000 – 20,000rpm 7,500rpm 10,000rpm 14,000rpm
Mild Steel 15,000rpm 10,000rpm 5,000rpm 3,500rpm 2,500rpm 1,500rpm 1,200rpm
Hard Steel /   Stainless Steel 12,000rpm 6,000rpm 3,000rpm 2,000rpm 1,500rpm 1,000rpm 750rpm
Wood 20,000rpm
Cutter speeds can vary greatly based on factors such as feed rates,   depth of cut, and the use of cutting fluid. The above chart is intended to   serve primarily as a comparison if cutter speeds in various materials.

Cutter Tip Chart

Prices

Part-No. Description Cut Angle Material Price
xen C1F000 AC-125 1/8″ x 4 1/2″ (3.17 x 114mm) solid carbide
30
Plastics  £        18.30
xen C1B000 AC-125 1/8″ x 4 1/2″ (3.17 x 114mm) solid carbide
40
Metals  £        18.30
xen C2XL AC-177 11/64″ x 7″ (4.36 x 177mm) carbide tipped
30
Plastics  £        19.95
xen C2XL AC-177 11/64″ x 7″ (4.36 x 177mm) carbide tipped
40
Metals  £        19.95
xen C3F000 AC-257 1/4″ x 7″ (6.36 x 177mm) carbide tipped
30
Plastics  £        23.95
xen C3B000 AC-257 1/4″ x 7″ (6.36 x 177mm) carbide tipped
40
Metals  £        23.95

 

 

Diamond Drag

The most common form of engraving in the trophy and awards industry is done using a non-rotating diamond-tipped tool to scratch lettering or designs in metal.

The process is frequently referred to as “diamond engraving,” “scratch engraving,” or “diamond drag” with the latter probably being the preferred terminology.

Diamond drag engraving can be performed on virtually all metals and in some applications, glass and plastics. In the awards industry, it is typically used as a quick, easy, and inexpensive method of engraving the pre-finished brass and aluminium plates on trophies and plaques. On colour plates, the diamond penetrates the coating and exposes the bare metal; a gold colour on the brass and silver on the aluminium. On material that has a clear coating, the engraving can be blackened with an oxidizing solution to add contrast.

Prices

Part-No. Description Cut Angle Material Price
xen DG1254 1/8″ x 5″ (3.17 x 127mm) diamond 120 Metals  £        25.50
xen DG171 11/64″ x 7″ (4.36 x 177mm) diamond 120 Metals  £        34.95
xen DG250 1/4″ x 7″ (6.35 x 177mm) diamond 120 Metals  £        34.95
xen DR125P 1/8″ x 5″ (3.17 x 127mm) rotating  diamond facetted Glass  £        76.60
xen DR171P 11/64″ x 7″ (4.36 x 177mm) rotating diamond facetted Glass  £        54.95
xen DR250P 1/4″ x 7″ (6.35 x 177mm) rotating diamond facetted Glass  £        54.95

 

Courtesy of Antartes Inc

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