Original Title: Drilling Technology Encyclopedia, Collected! Tips: Click [Window Fastener] on the top, click [..] in the upper right corner, and click [Set as
Star], so that we can meet every day. Drill, as the most common tool in hole
processing, is widely used in mechanical manufacturing, especially in the
processing of holes in cooling devices, tubesheets of power generation equipment
and steam generators. I. Characteristics of drilling Drills usually have two
main cutting edges, and when machining, the drill cuts while rotating. The rake
angle of the drill is getting larger and larger from the central axis to the
outer edge, the cutting speed of the drill is getting higher and higher when it
is closer to the outer circle, and the cutting speed decreases to the center,
and the cutting speed of the rotary center is zero. The chisel edge of the drill
is located near the central axis of rotation. The chisel edge has a large
secondary rake angle, no chip space and low cutting speed, so it will produce a
large axial resistance. If the chisel edge is ground to Type A or Type C in
DIN1414 and the cutting edge near the central axis has a positive rake angle,
the cutting resistance can be reduced and the cutting performance can be
significantly improved. According to the shape, material, structure and function
of the workpiece, the drill bit can be divided into many types, such as
high-speed steel drill bit (twist drill, group drill, flat drill), solid carbide
drill bit, indexable shallow hole drill, deep hole drill, trepanning drill and
interchangeable head drill bit. 2. Chip breaking and chip removal The cutting of
the drill is carried out in a narrow hole, and the chips must be discharged
through the drill edge groove, so the chip shape has a great influence on the
cutting performance of the drill. Common chip shapes include flaky chips,
tubular chips, acicular chips, conical spiral chips, ribbon chips, fan-shaped
chips and powdery chips. The Key of Drilling Machining: Chip Control When the
chip shape is not appropriate, the following problems will arise: ① Fine chips
block the cutting edge groove, affecting the drilling accuracy, reducing the
life of the drill bit, and even breaking the drill bit (such as powdery chips,
fan-shaped chips, etc.); ② Long chips entangle the drill bit, which hinders the
operation, causing the drill bit to break or preventing the cutting fluid from
entering the hole (such as spiral chips, ribbon chips, etc.). Expand the full
text How to Solve the Problem of Inappropriate Chip Shape ① The chip breaking
and chip removal effects can be improved by increasing the feed rate,
intermittent feed, grinding the chisel edge, installing the chip breaker and
other methods respectively or in combination, so as to eliminate the problems
caused by chips. ② Professional chip-breaking drill can be used for drilling.
For example, the addition of a designed chip breaker in the groove of the drill
breaks the chips into more easily removed chips. The debris is smoothly
discharged along the groove, and the phenomenon of blockage in the groove does
not occur. Therefore, the new chip-breaking drill obtains a much smoother
cutting effect than the traditional drill. At the same time, the short scrap
iron makes the coolant flow to the drill tip more easily, which further improves
the heat dissipation effect and cutting performance in the processing process.
Moreover,Tapered Rock Bit, because the new chip-breaking edge penetrates the whole groove of the drill bit, it can still maintain its shape and function after many times of
grinding. In addition to the above functional improvements, it is worth
mentioning that the design strengthens the rigidity of the drill body and
significantly increases the number of holes drilled before a single grinding.
III. Drilling accuracy The accuracy of the hole is mainly composed of the hole
size, position accuracy, coaxiality, roundness, surface roughness and hole burr.
Factors affecting the accuracy of the hole to be machined during drilling ① Bit
clamping accuracy and cutting conditions, such as tool holder, cutting speed,
feed rate, cutting fluid, etc.; ② Drill size and shape, such as drill length,
blade shape, drill core shape, etc.; ③ Workpiece shape, such as orifice side
shape, orifice shape,rock drilling tools, thickness, clamping state, etc. Reaming Reaming is caused by the oscillation of the drill during machining. The swing of the tool holder has a
great influence on the hole diameter and the positioning accuracy of the hole,
so when the tool holder is worn seriously, it should be replaced with a new one
in time. When drilling a small hole, it is difficult to measure and adjust the
swing, so it is better to use a drill with a thick shank and a small edge
diameter with a good coaxiality between the blade and the shank. When the
regrinding drill is used for machining, the reason for the decrease of hole
accuracy is mostly due to the asymmetry of the back shape. Controlling the
height difference of the cutting edge can effectively restrain the amount of
hole expansion. Roundness of the hole Because of the vibration of the drill bit,
the drilled hole shape is easy to be polygonal, and the lines like rifling
appear on the hole wall. Common polygonal holes are mostly triangular or
pentagonal. The reason for the triangular hole is that the drill bit has two
rotary centers during drilling, and they vibrate at the frequency of exchanging
once every 600. The main reason for the vibration is that the cutting resistance
is unbalanced. When the drill bit rotates for one turn, the resistance is
unbalanced during the second turn of cutting due to the poor roundness of the
processed hole. The last vibration is repeated again, but the vibration phase
has a certain deviation. Cause rifling pattern to appear on that walls of the
hole. When the drilling depth reaches a certain degree, the friction between the
drill edge and the hole wall increases, the vibration decreases, the rifling
disappears, and the roundness becomes better. The orifice of this pass is
funnel-shaped when viewed in longitudinal section. For the same reason,
pentagonal and heptagonal holes may also appear in cutting. In order to
eliminate this phenomenon, in addition to controlling the factors such as Chuck
vibration, cutting edge height difference, back and edge shape asymmetry,
measures such as improving drill rigidity, increasing feed per revolution,
reducing clearance angle and grinding chisel edge should be taken. Drill holes
on sloped and curved surfaces When the cutting surface or penetration surface of
the drill is inclined, curved or stepped, the positioning accuracy is poor, and
the tool life is reduced because the drill has a radial single-sided cutting
surface. To improve the positioning accuracy, the following measures can be
taken: 1. Drill the center hole first ； 2. Milling hole seat with end mill ； 3.
And that selection cut-in property is good Drill bit with good rigidity; 4.
Reduce the feed speed 。 Treatment of burrs During drilling, burrs will appear at
the entrance and exit of the hole, especially when machining materials with high
toughness and thin plates. The reason is that when the drill bit is about to
drill through, the material to be processed is plastically deformed. At this
time, the triangular part that should be cut by the cutting edge of the drill
bit near the outer edge is deformed and bent outward under the action of axial
cutting force, and further curled under the action of the chamfer of the outer
edge of the drill bit and the edge surface of the cutting edge, forming curling
or burrs. IV. Processing conditions of drilling In the catalogue of general
drill product sample book, there is a Reference Table of Basic Cutting
Parameters arranged by processing materials. Users can refer to the cutting
parameters provided to select the cutting conditions for drilling. Whether the
selection of cutting conditions is appropriate or not should be judged
comprehensively through trial cutting according to the machining accuracy,
machining efficiency, Borehole Drill Bits ,dth button bits, drill life and other factors. Drill life and machining efficiency On the premise of meeting the technical requirements of the machined
workpiece, whether the drill bit is used properly or not should be measured
comprehensively according to the service life and machining efficiency of the
drill bit. Cutting path can be selected as the evaluation index of drill life,
and feed speed can be selected as the evaluation index of machining efficiency.
For high speed steel drill bit, the service life of the drill bit is greatly
affected by the rotary speed, and is less affected by the feed per revolution,
so the machining efficiency can be improved by increasing the feed per
revolution, and the longer service life of the drill bit can be ensured.
However, it should be noted that if the feed per revolution is too large, the
chip will be thickened, resulting in difficulty in chip breaking. Therefore, the
range of feed per revolution that can successfully break the chip must be
determined through trial cutting. For cemented carbide drill, the cutting edge
has a large chamfer in the negative rake angle direction, and the optional range
of feed per revolution is smaller than that of high-speed steel drill. If the
feed per revolution exceeds this range during machining, the service life of the
drill will be reduced. Because the heat resistance of cemented carbide drill is
higher than that of high speed steel drill, the rotary speed has little effect
on the life of the drill, so the method of increasing the rotary speed can be
used to improve the processing efficiency of cemented carbide drill and ensure
the life of the drill. Rational use of cutting fluid The cutting of drill is
carried out in the hole with narrow space, so the type of cutting fluid and the
way of injection have a great influence on the life of drill and the machining
accuracy of the hole. Cutting fluid can be divided into two categories:
water-soluble and water-insoluble. The water-insoluble cutting fluid has good
lubricity, wettability and adhesion resistance, and also has anti-rust effect.
Water-soluble cutting fluid has good cooling property, no smoke and no
flammability. For the sake of environmental protection, the amount of
water-soluble cutting fluid is large in recent years. However, if the dilution
ratio of the water-soluble cutting fluid is improper or the cutting fluid
deteriorates, the service life of the tool will be greatly shortened, so
attention must be paid in use. Whether it is water-soluble or non-water-soluble
cutting fluid, the cutting fluid must fully reach the cutting point in use, and
the flow, pressure, nozzle number and cooling mode (internal cooling or external
cooling) of the cutting fluid must be strictly controlled. V. Re-sharpening of
drill bit Bit regrinding discrimination Criteria for re-sharpening of drill bits
are as follows: 1. Cutting edge Wear loss of chisel edge and edge land; 2.
Dimensional accuracy and surface roughness of the hole to be machined ； 3. The
color of the swarf , shape; 4. Cutting resistance (Indirect values of spindle
current, noise, vibration, etc.); 5. Processing quantity, etc 。 In actual use,
accurate and convenient criteria should be determined from the above indicators
according to the specific situation. When the wear loss is used as the
criterion, the best regrinding period with the best economy should be found out.
Because the main grinding parts are the back of the head and the chisel edge, if
the wear of the drill bit is too large, the grinding time is too long, the
grinding amount is too large, and the number of times of regrinding is reduced
(the total service life of the tool = the service life of the tool after
regrinding × the number of times of regrinding), which will shorten the total
service life; When the dimensional accuracy of the hole to be machined is used
as the criterion, the column gauge or limit gauge shall be used to check the
cutting expansion and non-straightness of the hole. Once the control value is
exceeded, it shall be re-sharpened immediately. When the cutting resistance is
used as the criterion, it can be stopped automatically immediately when the set
limit value (such as spindle current) is exceeded; When the processing quantity
limit management is adopted, the above discrimination contents shall be
integrated and the discrimination criteria shall be set. Method for sharpening
drill bit When re-sharpening the drill, it is better to use a special machine
tool for drill sharpening or a universal tool grinder, which is very important
to ensure the service life and machining accuracy of the drill. If the original
drill type is in good processing condition, it can be reground according to the
original drill type; if the original drill is defective, the rear shape can be
properly improved and the chisel edge can be grinded according to the use
purpose. Attention shall be paid to the following points during sharpening: 1.
Prevent overheating ? Avoid reducing the hardness of the drill bit; 2. Damages
on the drill bit shall be (Especially the damage on the edge surface of the
blade) is completely removed; 3. The drill pattern shall be symmetrical ； 4. Be
careful not to damage the cutting edge during sharpening. , and remove the burrs
after sharpening; 5. For cemented carbide drill bits ? The sharpening shape has
a great influence on the performance of the drill. The drill shape when leaving
the factory is the best drill shape obtained through scientific design and
repeated tests. Therefore, the original edge shape should be maintained when
re-sharpening. Window fixed tremolo number Tik Tok search: chuanggu1 chuanggu2
chuanggujgj [Disclaimer: This article is collected and published by Window
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[Window Fastener] at the top of this article, click [..] in the upper right
corner, and click [Set as Star], so that we can meet every day. Other product
drawings of window fixation: Window fixing factory gate A corner of the factory
yard fixed by the window Window fixing workshop corner Window fixed warehouse
corner Company profile Company Information "Chuanggu" is a well-known brand in
the fastener industry of doors, windows and curtain walls. Shanghai Chuanggu
Industry and Trade Co., Ltd. and Shanghai Chuanggu Fastener Manufacturing Co.,
Ltd. are two companies with a clear division of labor for the same investor. The
former mainly studies the fastening characteristics and demands of the door,
window and curtain wall industry, with the business purpose of meeting and
serving the customers of the door, window and curtain wall industry to the
maximum extent; the latter focuses on the research and development and
production of fasteners, providing necessary technical support for the former,
and also providing services and product support for other industries. The
company actively develops domestic and foreign markets, and its products rank
first in the domestic high-end market share, especially in Shanghai and its
surrounding areas. Its main products are self-tapping screws and self-drilling
self-tapping screws, which are highly praised by domestic and foreign
counterparts because of their stable quality. The production base of the company
is located at No.3566, Tingwei Road, Jinshan District, Shanghai, with a
construction area of 20000 square meters and more than 40 employees. The
workshop has 110 sets of advanced cold pier, drilling and thread rolling
equipment from Taiwan, and is equipped with a computer on-line detection system,
which provides a strong guarantee for the stability of product quality. At the
same time, it is equipped with an automatic feeding device and an oil throwing
device. To further improve production efficiency and reduce production costs,
the company currently produces 1.5 billion fasteners annually, and can further
expand production capacity with the expansion of the market. The company has a
semi-automatic packaging line and 3000 square meters of three-dimensional pallet
shelves. Window products currently have four series (stainless steel series,
carbon steel series, anchoring series, auxiliary tools and other non-standard
series), more than 2000 varieties, products are still further enriched and
developed. In order to better serve customers, the company constantly enriches
and improves its product structure. The company has a perfect quality management
system, advanced quality testing equipment and professional quality management
team. It is a long-term member of Shanghai Building Hardware Doors and Windows
Association and Curtain Wall Committee of Shanghai Building Decoration
Association. Company profile Company Information "Chuanggu" is a well-known
brand in the fastener industry of doors, windows and curtain walls. Shanghai
Chuanggu Industry and Trade Co., Ltd. and Shanghai Chuanggu Fastener
Manufacturing Co., Ltd. are two companies with a clear division of labor for the
same investor. The former mainly studies the fastening characteristics and
demands of the door, window and curtain wall industry, with the business purpose
of satisfying and serving the customers of the door, window and curtain wall
industry to the maximum extent; the latter focuses on the research and
development and production of fasteners, providing necessary technical support
for the former, and also providing service and product support for other
industries. The company actively develops domestic and foreign markets, and its
products rank first in the domestic high-end market share, especially in
Shanghai and its surrounding areas. Its main products are self-tapping screws
and self-drilling self-tapping screws, which are highly praised by domestic and
foreign counterparts because of their stable quality. The production base of the
company is located at No.3566, Tingwei Road, Jinshan District, Shanghai, with a
construction area of 20000 square meters and more than 40 employees. The
workshop has 110 sets of advanced cold pier, drilling and thread rolling
equipment from Taiwan, and is equipped with a computer on-line detection system,
which provides a strong guarantee for the stability of product quality. At the
same time, it is equipped with an automatic feeding device and an oil throwing
device. To further improve production efficiency and reduce production costs,
the company currently produces 1.5 billion fasteners annually, and can further
expand production capacity with the expansion of the market. The company has a
semi-automatic packaging line and 3000 square meters of three-dimensional pallet
shelves. Window products currently have four series (stainless steel series,
carbon steel series, anchoring series, auxiliary tools and other non-standard
series), more than 2000 varieties, products are still further enriched and
developed. In order to better serve customers, the company constantly enriches
and improves its product structure. The company has a perfect quality management
system, advanced quality testing equipment and professional quality management
team. It is a long-term member of Shanghai Building Hardware Doors and Windows
Association and Curtain Wall Committee of Shanghai Building Decoration
Association. Contact us Address: No.3566, Tingwei Road,down the hole bit, Jinshan District, Shanghai, China Window Fastener Mall shop. Shchuanggu. Com. Website 1: http://www.chuanggu.com. Website 2: Return to Sohu
http://shchuanggu.1688.com/ to see more Responsible Editor:. wt-dthtools.com
