(1) round drill
1. Standard round drill type
See fig. 5- 1- 1 for various scale names of standard round drills.
Figure 5- 1- 1 Various scale names of standard round drill types
Marshall Torkovsky (1899 ~ 199 1 year) first put forward the standard parameters of grinding ratio of modern circular drills, and the time was 19 19 years. According to Tolstoy's design, if the waist diameter is 100%, the desktop size is 53%. Overall height is 60% ~ 6 1% (including waist rib thickness 0.7% ~ 1.7%, crown angle 16.2%, and bottom depth 43. 1%), crown angle 34 30' and bottom angle 40 45. According to the above parameters, the round drill is called Torkovsky standard worker. In the United States, it has always been regarded as the standard of ideal works, and GIA still uses it as the standard measure to evaluate the proportion of diamond cutting.
When designing standard parameters, the guiding ideology of TOW is to maximize the "fire color" of diamonds, and at the same time, it also has strong brightness. The brightness of diamond mainly comes from reflected light and refracted light. Practice has proved that part of the incident light irradiated on the diamond will be reflected by the diamond surface, and the other part will be refracted into the diamond through the diamond surface. The smaller the incident angle, the less reflected light and the more refracted light. Conversely, the greater the incident angle, the more reflected light and the less refracted light (see Figure 5- 1-2).
Fig. 5- 1-2 Relationship between incident angle and reflected and refracted light.
The reflected light forms reflected light and flashing light on the diamond surface in two different ways: static and dynamic (that is, when the diamond rotates or the light source shakes, the diamond surface flashes or is bright or dark). The amount of reflected light and flickering light mainly depends on the size of the exposed surface area of the diamond (that is, the number and size of diamond facets and whether their arrangement is symmetrical).
Refracted light is closely related to the proportion of diamond, because most of the light entering the diamond from the crown of the finished diamond is reflected twice in the diamond pavilion and then transmitted out from the crown to the maximum extent. After repeated calculations, Tolkovsky found an ideal ratio (see Table 5- 1-2), in which the most critical ratio to achieve total internal reflection is the pavilion angle of 40 45'. In the case of a circular drill, the bottom angle of the longitudinal section of the special-shaped drill should also be about 40 45'. Too big or too small pavilion angle, in other words, too deep or too shallow pavilion angle will affect the total amount of light overflowing from the crown after total internal reflection, that is, it will affect the "fire color" of the diamond (see Figure 5- 1-3).
Table 5- 1-2 Comparison of various proportions of main varieties of round drills
In addition, the light from the crown actually overflows through two different ways: one part overflows from the desktop, and the other part overflows from the facets of the crown (namely, the crown main facet, the star facet and the upper waist surface). The light incident from the mesa and overflowing from the mesa is pure total internal reflection light, and there is no dispersion effect. However, the facet of the diamond crown actually acts as a prism, and the light overflowing from the facet of the crown will be dispersed. These two parts give people the impression that the relative primary and secondary relationship of different lights depends on the size of the desktop and the thickness of the crown (crown angle), as shown in Figure 5- 1-4, left: the desktop is too large, resulting in too high brightness and insufficient "fire color"; Right: the desktop is too small, resulting in strong "fire color" and insufficient brightness; Middle picture: The width ratio of the platform is moderate, which ensures the balance between "fire color" and brightness.
Fig. 5- 1-3 Influence of pavilion angle on diamond "fire color"
Figure 5- 1-4 Influence of table size and crown angle on diamond "fire color"
Judging from the current situation of the international diamond industry, GIA in the United States is dominated by Torkovsky standard workers, and most of Europe is dominated by Scan DN standard workers.
2. Other types of round drills
(1) Swiss workers
Generally, it is suitable for the finished product weight of 0.03~0.05ct. There are 34 facets up and down * * *: regular octagonal table top 1, crown surface 16, bottom surface 1 6, among which triangular facets account for the majority (see Figure 5-/kloc-0
(2) highlighting workers
It is obviously different from the standard round drill in that there are three facets (including the crown facet and the bottom facet) between the two main faces instead of two, so the number of 58 facets of the standard round drill is increased by 16, with a total of 74 facets (see Figure 5- 1-5(b)).
(3) Ace workers
Developed by new york "Ace Diamond Master" Company. It is characterized in that the tabletop is not octagonal, but regular dodecagon, so that the number of crown main faces and bottom main faces is correspondingly increased to 12, and the number of crown and bottom waist facets is correspondingly increased to 24, with a total of 86 facets. Other features are: the mesa is less than 50%, the star facet is higher than the crown facet, and the bottom facet is only about half of the bottom main facet (see Figure 5- 1-5(c)).
(4) Magna workers
Characterized by a regular decagonal table top, the crown main surface is divided into two parts, and the crown waist facet and the bottom waist facet are divided into three parts, so that the total number of facets reaches 102, namely 1 table top (regular decagon), 10 star facets, 20 crown main surfaces, 30 crown waist facets and 65442 bottom main surfaces.
(5) American round drill
It is considered to be the earliest round drill, which prevailed in Britain in the middle of19th century. Its crown arrangement is close to the modern standard round drill, but its overall height is almost equal to the waist edge diameter (only 60% of the modern standard work). Although the output is high, the fire color is not good. In addition, its countertop is small, about one-third of the diameter of the waist edge, while the bottom tip surface is large. Any side of the approximately octagonal mesa is almost in line with the edge lines of the adjacent star facets and the main surface of the crown (see Figure 5- 1-5(e)).
(6) Portuguese workers
Radial round drill, hexagonal table top, five layers of crown bottom, each layer has 16 facets, and the bottom tip has 162 facets. Mainly suitable for large diamonds (see Figure 5- 1-5(f)).
(7) Princess 144
This kind of grinder is developed on the basis of Magna, Ace and Highlight. Obviously different from the standard round diamond, each waist edge corresponding to the 16 crown and waist facet is polished into three facets, and a circle of 16 triangular facet and a circle of 16 diamond facet are added between the waist edge and the bottom waist facet, thus making the "fire color" of the diamond more intense and vivid, especially when the diamond rotates.
It is worth pointing out that there will also be square or rectangular princess works, usually with 57 facets and occasionally with 144 facets. Don't confuse them with "Princess 144" works.
(8) Screw workers
The table top is a regular dodecagon, with five facets at the crown and eight facets at the bottom, which are spirally arranged around the table top and the bottom tip (Figure 5- 1-5(h)).
(9) Imperial workers
The Imperial Palace was developed by Hong Kong Yufu Group (International) Co., Ltd in recent years. It is characterized in that on the basis of the standard round drill, the star facet and upper and lower waist surfaces of the standard round drill are divided into two parts, and 96 faces are cut at the waist, thus forming 194 faces. Even in places with weak light, the peripheral parts of imperial workers can emit bright light (Figure 5- 1-5(i)).
(10) "Eight Arrows and Eight Hearts"
It is a variant of the standard round drill type and is very popular in recent years. It is characterized by strong symmetry, small change of tangent angle, and the ratio is not within the ideal range (see Figure 5- 1-5(j)).
(1 1) single round drill
It is very common in the cutting and grinding of sub-drills. The crown has only one table and eight main faces, and the pavilion has only eight faces, *** 17 faces (see Figure 5- 1-5(k)).
Figure 5- 1-5 Different types of circular drill cutting
(2) Shaped drill
1. Common irregular drills
There are seven kinds of common irregular drills: horse eye drill, heart-shaped drill, pear-shaped drill, oval drill, emerald drill, rectangular drill and princess drill (see Figure 5- 1-6).
Figure 5- 1-6 Common special-shaped drill varieties
(1) horse eye drill
Horse-eye diamond, also known as "olive diamond" and "boat diamond", is known as the "cutting queen" in modern diamond polishing.
The aspect ratio of horse eye drill is1.75:1~ 2.25:1,followed by 2.25: 1 ~ 2.50: 1, greater than 2.50: 1 or less than 65438.
(2) Pear drill
Pear-shaped drill, also called tear drop drill. The best aspect ratio of pear-shaped drill is1.50:1~1.75:1,1.75:1~ 2.00:1or/kloc.
(3) Heart drill
Heart-shaped drill is a kind of radial cutting that combines the processing technology of round drill and pear-shaped drill, which was invented by ancient Indian craftsmen. Triangular flaky twin stones are most suitable for heart-shaped drills, and the output varies from stone to stone.
Features of the heart-shaped drill: ① The notch at the top of the heart tip is not counted, and the bottom tip should be located in the geometric center; (2) The inclination of the main surface of the crown is 33 ~ 34; (3) The inclination of the main surface at the bottom of the heart and shoulder should be 4 1, and the inclination of the abdomen is slightly larger, about 42; ④ The length and width must be basically equal; ⑤ The finished waist edge is generally polished into a series of small waist edges.
(4) Elliptical drill
There are two types of elliptical drills: standard and slender. Standard aspect ratio1.3:1~1.5:1; The length-width ratio of slender type is1.5:1~ 2.0:1.
(5) Emerald type drill
Emerald cutter is a kind of polygonal stepped cutter with chamfering, which is usually rectangular. The number of engraving layers is three layers, two layers and four layers. Emerald diamond is the most popular cutting and shaping after round diamond, and it is known as "Cinderella" in the modern irregular diamond group.
The aspect ratio of emerald is1.1:1~1.50:1according to the original stone size.
(6) Rectangular drill
Rectangular drills are generally rectangular, and the aspect ratio is often larger than that of jadeite grinders. Because cutting and grinding rectangular drills take care of themselves, their waist blade shapes and various proportions can be unusually flexible: some can be very long and thin, others can be very short, the aspect ratio is close to a square, and the two short sides can be different, thus forming an isosceles trapezoid with a point taper.
Rectangular drill is listed as a common special-shaped drill, mainly because it is widely used in the assembly of jewelry, so it is generally small in size.
(7) Princess type
The waist rib is generally square or rectangular, with radial facets at the crown and sharp facets at the bottom, generally with 57 facets, and occasionally the number of facets can be as high as 144. Be careful not to confuse it with the "Princess 144" drill. In addition, the gear shaper was once called "princess worker", so we should pay attention to the difference.
2. Rare irregular drilling
There are many rare irregular drills, which can be divided into three types and 12 series:
Radial rose series, saddle pad series, "lady" series, star series.
Step platform series, polygon series
Hybrid Belize series, gorgeous series, princess series, tooth series, "five golden flowers" series, arbitrary series.
(1) Rose Series
Rose workers originated in India more than 400 years ago. Among the world-famous diamonds, Mughal the Great, orlov and Mountain of Light are all rose workers.
Rose worker is the originator of modern radial grinder. Generally, flat-bottomed non-abrasive facets are adopted, and the crown is a circular arch. Arches vary in height, but they all have facets. Most of the raw stones used are relatively thin, but care should be taken when processing, and the proportion should not be too particular or too "hot".
There are many kinds of rose worker ants, and the main varieties are shown in Figure 5- 1-7.
Figure 5- 1-7 Different types of rose workers
(2) Saddle pad series
Ancient saddle pad diamonds were rectangular or square, with rounded corners and slightly protruding sides. In addition to retaining the above style, the modern saddle pad drill is close to the standard round drill in crown lobe arrangement, but the bottom is quite different (see Figure 5- 1-8).
Figure 5- 1-8 saddle pad series
(3) Ladies Series (see Figure 5- 1-9)
Figure 5- 1-9 ladies series
(4) Semi-series (see Figure 5- 1- 10)
Fig. 5- 1- 10 semi-series
(5) Star series (see Figure 5-1-1)
Figure 5-1-1/star series
(6) Desktop series
The table top is one of the oldest grinding machines, only slightly modified on the octahedral original stone. Grind a larger mesa and a smaller bottom tip from the top surface of the crystal, and then polish each crystal surface (see Figure 5- 1- 12).
Figure 5- 1- 12 Table Series
(7) Polygon series
They belong to the same step grinder, but the waist edges are different in shape, as shown in Figure 5- 1- 13.
Figure 5- 1- 13 Polygon Series
(8) Byron series
1970 10 was created by the south African master of grinding and drilling, Mr basil watermeyer. He just changed the first letter "M" in his wife's name to the first letter "B" to show the crystallization of their love.
Using a step grinder at the top and a radial grinder at the bottom, both of which are improving the yield and luster. A square diamond has 62 facets and an emerald diamond has 70 facets (see Figure 5- 1- 14).
Fig. 5- 1- 14 An Baili series
(9) Section cutting
The gear shaper was first invented in London in 196 1 by a man named arpad Reggie, formerly known as "Princess Worker". It's made of thin sheets that are not commonly used in jewelry industry, with rows of 4 1 V-shaped grooves at the bottom, and the waist rib shape can be "cut" to spell out various beautiful patterns at will (see Figure 5- 1- 15). "More flexibility, but less fire."
Fig. 5- 1- 15 tooth series
(10) "Five Golden Flowers" Series
1988 was created by Gaby Torkovsky, consultant of Central Diamond Marketing Organization (CSO), and there are five * * * models, all named after the flower name. It is mainly designed for rough stones with low color grade and poor crystal shape (see Figure 5- 1- 16).
Figure 5- 1- 16 "Five Golden Flowers" Series
(1 1) pictographic series
This series of grinders have figured out the shapes of horse's head, butterfly, flower and fish according to the shape of the original stone waist, and the arrangement of facets is naturally irregular (see Figure 5- 1- 17).
Figure 5- 1- 17 pictographic series