Fatiamento de Precisão de Vidro Óptico com Fio de Diamante em Laço: 30.5 Dados de Teste de Barra mm

Abstrair: Este relatório de aplicação cobre um teste de fatiamento reto de alta precisão em vidro óptico
fornecido por um cliente europeu. A peça de trabalho era uma barra de 30.5 mm de diâmetro, cortada em secções 15 mm de comprimento numa
máquina de corte com fio de diamante em laço de pórtico ESO-GM, com óleo de corte como meio de arrefecimento e um diamante totalmente revestido
fio. Resultados medidos em três secções: variação total de espessura (TTV) 0.003-0.008 milímetro, tolerância de espessura
±0,141 mm em relação a um 15.000 mm nominais, surface roughness Ra 0.58-1.06 μm, e desgaste máximo de arestas
4.9-6.2 μm. Matching machine structure, o método de corte com óleo, seleção do fio e parâmetros do processo para o
comportamento frágil do vidro óptico manteve a remoção de material estável e preservou a precisão dimensional das secções e a qualidade da superfície cortada
dentro de uma faixa utilizável.

Teste de amostra para um cliente europeu | Processo de corte em laço de fio diamante

Overview of the Optical Glass Precision Slicing Test

This test was run on optical glass supplied by a European customer, with high-precision straight slicing as the
main requirement. Optical glass sits firmly in the hard, brittle family: dureza é bastante elevada, brittleness is
pronounced and fracture toughness is low. Once the diamond grains start abrading continuously, poor control of the
cutting load or of the temperature in the cutting zone concentrates stress inside the material, and that is where
lascar, micro-fissuras, end-face damage and section dimensional deviation come from. The work therefore went at
machine structure, método de corte, wire selection and process parameters as one set, so the slicing stayed stable and
section dimensions and cut-surface quality could be held to the tolerances required for
corte óptico de vidro.

Because optical glass asks for dimensional accuracy, end-face quality and edge integrity at the same time, Ensoll
applied a diamond wire loop process matched to those characteristics. On the machine side the choice fell on a
dedicated gantry diamond wire loop cutting machine. Its rigidity and running stability give the workpiece a firm
clamping base and hold the wire on a steady path, which cuts down the effect of machine vibration and motion error on
the cutting trajectory and on section dimensions. On the consumable side, a diamond wire matched to optical glass
keeps the grains removing material at a steady rate, so a change in wire condition does not turn into a change in
section quality. For cooling and lubrication, cutting oil was used: it improves lubrication and heat dissipation at
the contact zone between wire and glass, lowers friction and heat build-up through the cut, and reduces what a local
temperature rise does to the cut face. On top of that, wire running speed and feed rate were set against the
properties of the material and the target section length, keeping the cutting load inside a suitable band and avoiding
the local overload and edge breakage that an aggressive feed produces. Máquina, fio, oil cutting and parameters
matched as one set kept the process stable and brought section dimensional accuracy, consistência da espessura,
cut-surface quality and edge integrity under control — a workable process basis for high-precision straight
slicing of optical glass. The same parameter logic applied to flat work is set out in our
BG38 glass sheet slicing test.

1. Test Object: Informação Básica

• Material: vidro óptico
• Dureza: aproximadamente MH 6 Para 7
• Dimensões da peça de trabalho: diâmetro 30.5 milímetro
• Dimensões de corte: 15 milímetro (L) x 30.5 milímetro (φ)

2. Seleção de Máquina e Fio

Tipo de máquina: ESO-GM. Given the brittle behaviour of optical glass and the high-precision straight
slicing requirement, A Ensoll selecionou a ESO-GM, the gantry machine built
for this class of work. It holds running stability and trajectory accuracy through the cut, reduces the effect of
machine vibration and load fluctuation on machining quality, limits the chipping, micro-cracking and dimensional
deviation that uneven loading would otherwise produce, and so improves dimensional accuracy, cut-surface quality and
edge integrity in optical glass sections.

• Tipo de fluido de corte: óleo de corte. Cutting oil is used as the cooling and lubricating medium. It improves
  lubrication and heat dissipation in the contact zone, lowers friction and heat build-up through the cut, and reduces
  the thermal and local stress variation the glass sees. That lowers the risk of chipping, micro-cracks and end-face
  damage, which helps dimensional stability, surface quality and edge integrity.
• Tipo de fio: totalmente revestido. A fully coated diamond wire raises the bond strength between grains and
  the steel core and keeps grain distribution even, so the wire removes material continuously and steadily through the
  cut. It reduces the effect of grain pull-out and wire wear on the cutting state, which limits dimensional variation
  and edge damage when slicing optical glass.

3. Método de Corte e Vantagens da Máquina

Gantry cutting method. The gantry structure gives the machine high overall rigidity and running
estabilidade, and the top-down vertical feed helps keep the Loop de fio de diamante on a stable
path, reducing the effect of load variation on kerf position and dimensional accuracy in optical glass sections. O
machine also carries a mist extraction system that clears the oil mist produced during cutting, keeping the work zone
clean and the cutting area in good condition for a stable run.

Sistema inteligente de controlo de tensão. The system adjusts wire tension in real time according to the
machining state and supports both constant-tension and variable-tension modes, so the wire runs steadily through the
cut. Stable tension reduces trajectory drift and cuts the risk of wire breakage that tension variation brings, o que
narrows the local load changes seen at the cut and helps control section dimensions and edge quality across the
batch.

Breakpoint resume. If the wire breaks or the machine stops abnormally, the system records the
current cutting position and the associated running state. After a wire change the cut resumes from that position,
which reduces the re-positioning error and repeat cutting that would otherwise affect cut position and quality, and it
keeps material loss down while the slicing run stays continuous.

High-rigidity one-piece cast iron frame. The one-piece cast iron frame raises overall stiffness and
vibration resistance, lowering the effect of structural vibration and deformation on the wire path. For a hard,
brittle material such as optical glass, that rigidity reduces load fluctuation during the cut and gives the dimensional
precisão, cut-surface quality and edge integrity of precision slicing a reliable machine basis.

4. Definições de Parâmetros e Método de Arrefecimento

The parameter set below was used for the whole run, and the sections reported in section 5 all came off it. Fio
tension and wire speed are the two settings that carry most of the load control; the cutting load reading is what the
operator watches to keep the wire inside its working band.

Parâmetro	Valor
Diâmetro do fio (milímetro)	0.35 x 1880
Velocidade de deslocamento do fio (mm/min)	10
Largura de corte (milímetro)	30.5
Tensão do fio de corte (N)	140
Velocidade do fio (M)	24
Tempo do arco do fio (s)	60
Carga de corte (N·m)	20

5. Eficiência de Corte e Resultados

5.1 Dados de teste TTV (milímetro)

TTV (Variação total da espessura) was measured with a nine-point grid, dual-probe thickness method on a vacuum-chuck
stage, applied to sections produced by diamond wire loop cutting. The sections measured 15 milímetro (L) x 30.5 milímetro (φ),
com uma espessura nominal de 15 milímetro. Before measurement the instrument was thermally stabilised and calibrated with a
standard thickness block to reduce zero drift and systematic error. Após limpeza sem poeira, each sample was centred
on the vacuum chuck and held by negative pressure, so that warping, tilt and position shift during measurement had
less effect on the thickness readings. Thickness data were then collected in sequence at the preset nine grid
positions, and the difference between the largest and the smallest reading across those points was taken as the TTV
of that sample, used to evaluate thickness uniformity and machining consistency. The procedure follows the method
explained in nine-point TTV measurement.

Amostra	Leituras de espessura de nove pontos (milímetro)	Tmax	Tmin	TTV
S01	15.056, 15.057, 15.058 / 15.059, 15.060, 15.061 / 15.062, 15.058, 15.057	15.062	15.056	0.006
S02	15.112, 15.113, 15.114 / 15.115, 15.113, 15.114 / 15.113, 15.114, 15.115	15.115	15.112	0.003
S03	15.135, 15.137, 15.138 / 15.140, 15.141, 15.142 / 15.143, 15.138, 15.139	15.143	15.135	0.008

Avaliação: Looking at the nine-point readings for the three sections, S01 measured between 15.056
e 15.062 milímetro, S02 between 15.112 e 15.115 mm and S03 between 15.135 e 15.143 milímetro, giving TTV values of 0.006 milímetro,
0.003 mm e 0.008 mm respectively. S02 held the tightest thickness uniformity and S03 showed the widest spread, but
every section stayed inside 0.008 milímetro. Thickness variation across the measured areas is therefore small, which says the
wire ran steadily and the cutting state held through the run, and thickness consistency meets what high-precision
optical glass slicing asks for.

5.2 Dados de Tolerância à Espessura (milímetro)

A tolerância à espessura foi medida pelo mesmo método da grelha de nove pontos, com 15.000 mm conforme calculada a espessura nominal. O
o desvio de cada ponto medido em relação ao nominal foi calculado, e a máxima deformação positiva, desvio máximo negativo
tolerância geral de espessura foram coligidos, to assess dimensional accuracy and machining consistency of
the optical glass sections.

Amostra	Espessura média (milímetro)	Desvio da espessura (milímetro)
S01	15.059	+0.059
S02	15.114	+0.114
S03	15.141	+0.141
Máxima deformação positiva	+0.141	+0.141
Máxima deformação negativa	0	0
Tolerância de espessura	±0.141	±0.141

Avaliação: Com 15.000 mm as nominal, the three sections averaged 15.059, 15.114 e 15.141 milímetro,
corresponding to deviations of +0.059, +0.114 e +0.141 milímetro. All three sat on the positive side, the maximum positive
deviation was +0.141 mm and no negative deviation was recorded, so the overall thickness tolerance is quoted as
±0.141 mm. Average thickness also rises steadily with sample number, which shows the batch carried a small
systematic bias towards the thick side. The bias is regular rather than random, so it is a compensation matter rather
than a process-capability one.

5.3 Dados de Rugosidade de Superfície Ra (μm)

Rugosidade da Superfície (Ra) foi medida de acordo com a ISO 4287 com um perfilador de estilete. Three representative positions were profiled
on the cut face of each section — centro, meio-esquerda e meio-direita — and Ra was calculated at each position
to assess the cut surface and machining quality.

Amostra	Ra-1	Ra-2	Ra-3	Ra médio
S01	1.02	1.08	1.07	1.06
S02	0.55	0.61	0.58	0.58
S03	0.82	0.91	0.88	0.87

Avaliação: Measured by the three-point method, average Ra came out at 1.06, 0.58 e 0.87 μm
for S01, S02 and S03, so the whole set falls in the 0.58-1.06 μm range. The difference between measuring
positions on a single section is small, which means the cut face is fairly even and the process holds surface quality
under control. S02, which also held the best TTV, returned the lowest Ra — the two indicators moved together on
this run.

5.4 Dados de lascamento de borda (μm)

Chipping was measured by optical imaging on a toolmaker’s microscope to quantify edge defects on the sections, o que
medidos 15 milímetro (L) x 30.5 milímetro (φ) after cutting. As bordas das amostras foram limpas antes da medição, and the instrument
magnification and measuring scale were calibrated. The edge regions were then scanned under the microscope,
recognisable chips were located and measured, and the defect size at each point was recorded, giving an assessment of
edge quality and cutting performance.

Amostra	Posição 1	Posição 2	Posição 3	Posição 4	Maximum chipping
S01	4.6	5.2	4.9	5.8	5.8
S02	3.8	4.5	4.1	4.9	4.9
S03	5.1	5.7	5.4	6.2	6.2

Avaliação: Inspected by the four-point method, the largest chip measured 4.9-6.2 μm across
the three sections, with the individual measurement points sitting close together. Defect sizes are small and the
difference between samples is limited, which indicates a stable cutting state through the run and good edge integrity
on the sections.

6. Conclusão

The optical glass in this run sliced well, and the result came mainly from matching a dedicated gantry machine, o
oil cutting method and the process parameters as one set. Optical glass is a classic hard, frágil: dureza
is fairly high, brittleness is pronounced and fracture toughness is low, and during diamond wire loop cutting the
continuous abrasion of the grains means that local cutting load and heat build-up easily concentrate stress, o que
produces chipping, micro-fissuras, an uneven cut face and section dimensional deviation. Aimed at the machining
behaviour of the material and the requirement for high-precision straight slicing, machine selection, método de corte
and parameters were all adjusted in a targeted way, holding section dimensional accuracy, thickness consistency and
cut-surface quality in check while the cutting process itself stayed stable.

First, machine selection. Given what optical glass slicing demands in motion stability, máquina
rigidity and cutting accuracy, a dedicated gantry diamond wire loop cutting machine was selected. The gantry structure
provides good overall rigidity and running stability, which gives the workpiece firm clamping and the wire a reliable
mechanical basis for steady running, and reduces the effect of machine vibration, motion error and wire running
fluctuation on the cutting trajectory. Stable feed and motion control also narrow the cutting-load variation, so wire
and glass stay in a comparatively steady relative motion, which lowers the risk of dimensional deviation and local
chipping and gives high-precision slicing a stable machine basis.

Segundo, método de corte. Optical glass is markedly brittle and sensitive to thermal effects during
corte, so oil cutting was used, with cutting oil as the cooling and lubricating medium. Cutting oil improves
lubrication and heat dissipation in the contact zone between wire and glass, lowering friction and heat build-up and
reducing the effect of local temperature rise and thermal stress on the material. Steady cooling and lubrication also
help hold the cutting zone in a consistent state and reduce the cutting fluctuation that friction or concentrated heat
would cause, so chipping, micro-cracks and end-face damage become less likely and the cut surface and edge integrity
improve.

Terceiro, parâmetros do processo. Against the material properties and the target section size, fio
running speed and feed rate were matched accordingly. Parameters were set to keep the wire running stably and material
removal even, avoiding a feed rate so high that the cutting load climbs, and avoiding a combination that produces
local heating, stress concentration and brittle fracture. The targeted adjustment kept material removal comparatively
steady and, while still meeting machining efficiency, reduced impact and load fluctuation through the cut, o que
improved thickness consistency, cut-surface quality and edge integrity.

Taken together, the results for section dimensional accuracy, tolerância de espessura, rugosidade superficial (Ra) e
cut-edge quality show that, with a dedicated gantry cutting machine, oil cutting and suitable parameters working
together, diamond wire loop cutting meets the requirements of high-precision straight slicing for optical glass. O
samples performed steadily in dimensional accuracy, consistência da espessura, cut-surface quality and edge integrity,
which indicates that matching machine structure, cooling and lubrication method and process parameters to the
properties of the material improves the removal state and process stability, and offers a process reference for
high-precision straight slicing of optical glass.

Perguntas Frequentes

Can a diamond wire loop slice a 30.5 mm optical glass rod into 15 mm sections?

Sim. In this test a rod of 30.5 mm diameter was cut into sections 15 mm long on an ESO-GM gantry machine, com
cutting oil and a fully coated 0.35 x 1880 mm wire running at 10 mm/min travel, 140 tensão N e 24 velocidade do fio m/s.
Measured TTV was 0.003-0.008 milímetro, thickness tolerance ±0.141 mm, average Ra 0.58-1.06 μm and maximum
lascar 4.9-6.2 μm.

What TTV can be held when slicing optical glass with a diamond wire loop?

In this run TTV was 0.006 milímetro, 0.003 mm e 0.008 mm across three sections, measured by the nine-point grid method
on a vacuum chuck against a 15 mm de espessura nominal. All three sat inside 0.008 milímetro, which is the sort of uniformity a
precision slicing process needs before any lapping or polishing step.

Why use cutting oil instead of a water-based coolant for optical glass?

Cutting oil lubricates and cools the contact zone between wire and glass. Here it improved heat dissipation in the
cutting zone and lowered friction and heat build-up, which cut the thermal and local stress variation the glass sees
and lowered the risk of chipping, micro-cracks and end-face damage. The machine carries a mist extraction system to
clear the oil mist produced during the cut.

How much edge chipping should be expected on sliced optical glass?

In this test maximum chipping came to 4.9-6.2 μm measured by optical microscopy, with four positions checked
per section. Individual measurements were tightly grouped, so the chip size is small and consistent rather than
occasional deep damage — an edge condition that normally cleans up in a light finishing pass.

Why did all three optical glass sections come out thicker than nominal?

Against a 15.000 mm nominais, the sections averaged 15.059, 15.114 e 15.141 milímetro, so every one ran on the plus side
by 0.059 Para 0.141 milímetro. Because the deviation moves steadily with sample number it is a systematic offset, not random
scatter, and the practical fix is dimensional compensation on the next run rather than a change to the cutting
parameters.

Conteúdo técnico revisto pela equipa de engenharia da Ensoll – um fabricante de laços de fio de diamante com 10+ anos de experiência em produção.