Successful grinding wheel dressing

The accuracy of a cutting tool depends on the accuracy of the grinding wheel that produces it. Therefore, the shop that manufactures cutting tools must accurately correct and trim the shape of the grinding wheel to produce consistent high-precision tools that meet the increasingly sophisticated parts requirements of customers.
Grinding wheel correction and dressing for shop tool grinders can be performed on-line or off-line systems, each with its own advantages and disadvantages.
The dedicated correction and finishing machine for off-line dressing is independent, so off-line dressing does not interfere with the grinding operation. These machines adapt to the entire grinding wheel assembly and they serve many grinding machines in the same shop. The debris produced by the dressing can be kept outside the precision grinding machine. “Most cutting tool shops use our systems to service 10 or more grinding machines,” says Bill Freese of Rush Machinery .
Rush Machinery is a company that manufactures calibration and finishing machines. In the workshop where these machines are used, two sets of grinding wheels are used, one set of grinding wheels works normally, and at the same time, each worn grinding wheel assembly is removed from the automatic grinding wheel device of the grinding machine, and these components are corrected and trimmed, and then they are put back on the grinding wheel device. .

1
The grinding wheel performance of the grinding tool depends on the correction and finishing

Off-line dressing machines are particularly advantageous for workshops that regrind cutting tools. These workshops usually perform frequent wheel changes after a short period of time, while the off-line system ensures that the wheel assembly is ready before replacement and the machine does not have to wait.
If the tool shop is mass-produced, it usually uses two sets of grinding wheel assemblies, Freese said. When a set of grinding wheel assemblies is working, the operator corrects and trims another set of components on an off-line machine. The grinding wheel is balanced on the connecting sleeve and the trimmer re-stores the relative value of each grinding wheel diameter relative to the diameter of the additional grinding wheel in the assembly.
Ruch's manual offline system has three grades: the first is the basic type, and the workshop is mainly used for disc wheels or angle grinding wheels. The second machine has a video optics system with a highly magnified optical lens and video camera. The shop trims the wheel radius according to the various circular templates displayed on the machine screen.
Most of the third machine tools are commonly used in cutting tool shops, equipped with video systems, highly scalable video cameras and computers, running computer-aided design (CAD) programs that display multiple layers on the screen. With the third machine shop, any combination of radius and angle can be produced to produce the desired wheel profile. This class of machine speeds up the correction and finishing of complex wheel profiles, such as the grinding of drill bits, Freese said.
The inline finishing system is designed for long unattended grinding operations because the system is installed in the grinding machine and runs automatically. This system provides high precision finishing of CNC control.
“I always recommend online calibration and finishing, mainly because the system is the actual mandrel and spindle correction and dressing wheel for the grinder being used,” said Tim Finn, senior co-application engineer at Saint-Gobain Abrasives. He said this because of recent technological advances that enabled the shop to use diamond dressing rolls to trim diamond wheels online and improve the inline finishing process.

1
Off-line calibration and finishing system keeps the sharpener wheel assembly working continuously

The diamond wheel provides a high metal removal rate, which greatly reduces the part production cycle. This wheel is durable and requires very little repair and little machine power to run. However, because the grinding wheel is not easy to grind and maintain its original shape, the workshop cannot effectively trim these grinding wheels online. And because the spindle of the inline finisher does not provide sufficient speed, the diamond dressing rolls wear out quickly.
However, Saint-Gobain's three new products: the Unival G-Force diamond cutting wheel, the MaxTorq dressing unit and the copper profile roller, improve the technology for online dressing of diamond wheels.
The Unival G-Force easy-to-cut diamond wheel does not require bar trimming or trimming with a diamond roll after forming. Bar dressing is an additional process that exposes the cutting abrasive of the grinding wheel and is necessary when machining rock-hardened resin-bonded grinding wheels. This type of grinding wheel used to be used for grinding high speed steel and carbide tools in the workshop. Finn said that the resin bonded grinding wheel will not be used for cutting unless it is trimmed with a rod after calibration.
His company's G-Force wheel is a hybrid polyimide metal bond. The reason for making them easy to cut is that their binders are extremely strong and the grinding wheel does not need a lot. The use of a diamond dressing roller to trim a diamond wheel requires a high speed, and to date, the in-line dressing roller spindle has been operated at 3,600 r/min, which is not sufficient for this task. However, Saint-Gobain's MaxTorq dressing unit provides a spindle speed of 12,000 r/min through a DC brushless motor, allowing the dressing wheel to reach 5,500 m/min (18,000 sft/min) with a 150 mm (6 in.) diameter dressing roll. speed.
Finn says that the shop can economically calibrate the diamond wheel by trimming the spindle at high speed and slowing the wheel speed to 1000 feet per minute. However, new abrasives must be exposed to the grinding wheel or they will not be cut.
In order to ensure that the new abrasive is exposed, Saint-Gobain has developed a copper profile roller, which is characterized by a circumference of diamond particles with an average width of 0.250 inches.
Although most workshops trim the traverse rate (the rate at which the dressing rolls traverse the grinding wheel) is a measure of the yield of the trimming process. That is, the amount of traverse rate per revolution of the grinding wheel - the ratio of the number of times the dressing roller "hits" the sand on the surface of the grinding wheel, Finn said. The ideal overlap rate is once, any more times, which means that the dressing roller hits the same point on the grinding wheel more often than it has to.
For example, an overlap ratio of 10 means that the diamond particles of the grinding wheel are 10 times in the same click before the continuation. “The key to trimming diamonds with diamonds is to use thin rollers and traverse the wheels as quickly as possible,” says Finn.
Saint-Gobain's brazed profile rolls do not need to be reground to restore their tip geometry. This is crucial because the machine eliminates the downtime associated with grinding removal and installation, Finn said. With conventional rollers, the shop must be reground 4 times during the life of the roll, requiring 30-50% of the price of a new roll for each cost.
In the field testing of these three products of tool grinding machines by Rollomatic, Anca Inc. and Walter Grinders , carbonized ceramic diamond wheels were used for high-speed diamonds. The rollers trim the threads of the carbonized milling cutter, the toggles on the roughing tool and the grooves and the toggles on the high speed steel end mill. In most instances, the part's machining cycle is reduced by 30%, and the production of parts is doubled each time the wheel is trimmed. Prior to this, these test shops used resin-bonded grinding wheels, which had to be removed from the grinding machine and trimmed on off-line machines.

Electroformed Test Sieve

Precision electroforming 75 Test Sieve, Material Screening and Testing in Laboratory.

The electroformed sieve with precise aperture size, smallest tolerance. standard diameter have 5mm, 200mm.

ISO3310 standard, use punch plate, solid and durable. price is higher than common sieve, suitable for demanding industries.

our sieve won the customer's praise

Laboratory Test Sieves,Standard Sieve,Laboratory Standard Test Sieve,Electroformed Test Sieve

Xinxiang Xin Ming De Machinery Co., Ltd. , https://www.xmdsieve.com