VIDEO
CNB31/34 MOTORISED CHARPY NOTCH BROACHING MACHINE
 
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VIDEO
MOTORISED MACHINE OPTIONS: 'U' Notch Specimens
 
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VIDEO
MOTORISED MACHINE OPTIONS: 0.45" Diameter Specimens
 
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Machine Design and Method of Operation

Machine Design:

The machine is simple to operate and of robust construction, with large removable panels to provide access for routine maintenance. The design of the machine provides a comfortable working height.
 
The cutting operation is achieved by drawing a specially designed multi-toothed broach across the specimen. The broach is drawn into the machine by precision twin lead screws via a geared mechanism to ensure the broach cuts perpendicular to the specimen clamp, limit switches are fitted for end of stroke travel.
 
The lead screws are matched with the travel nut to ensure minimum-operating clearances, while spring loaded safety guards ensure swarf and debris cannot enter into the lead screws and nuts.

Fixed Speed Drive:
 

Once the notch depth has been set and the specimen clamped in position, the machine operation is activated via lower and raise push- buttons. An additional stop button is fitted for emergency use.
 

The machine operation is controlled by the lower and raise push- buttons, which forward and reverse the machine motor, resulting in the broach cutting and return strokes being at a fixed speed. The motor has thermal overload protection to protect the drive mechanism.

Variable Speed Drive:
 

Once the notch depth has been set and the specimen clamped in position, the machine operation is activated via a lower and raise switch. A graduated knob controls the speed the broach cuts and the broach return speed is factory set at a constant fast speed. A  stop button is fitted for emergency use.
 

The motor is controlled via a variable speed, frequency converter thyristor drive and the pre-programmed P.L.C. ensures motor overload does not occur to protect the drive mechanism.

Guards:

The machine guards totally enclose the drive motor and operating mechanism.

A broach guard is fitted to comply with safety regulations; limit switches prevent motor operation when the guards are open.

Method of Operation:
  

A hand-operated clamp is mounted on the machine top plate at a comfortable working height and ensures that the specimen is held accurately and securely in position. It is fitted with adjusting screws and an end stop to ensure correct specimen positioning. A micro-adjustor provides manual adjustment for broach depth of cut and hence the final notch depth. Once set, the adjusting screws provide repeatability for the next specimen.

The clamp can accommodate 10mm square & 10mm x 7.5/6.7mm rectangular sub-size samples. For 10mm x 5.0/2.5mm rectangular sub-size samples a broach keep “W” is required and for circular specimens a different clamp block is required, see accessories.

The broach can easily be removed for re-sharpening or replaced to cut a different type of notch.

 
VIDEO
MOTORISED MACHINE OPTIONS: Sub-Size Specimens
 
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The sample is secured in the machine by the clamp. A light coating of cutting oil (RTD recommended) is applied to the broach and the lower push-button/switch is operated which draws the broach through the specimen to produce an accurate notch profile. After the notch has been cut, the sample is removed, the broach raise push-button/switch operated, which raises the broach and the broach teeth are cleaned, ready for the next sample.

Multi-notch Attachment:

There are 2 options for multi-notch samples.
A) 0.45” diameter and 10mm square sample attachment.
B) 10mm square sample attachment only.

The multi-notch attachment allows for single and multiple notches to be produced in 10mm square and/or 0.45" diameter specimens. See accessories.

This option is normally fitted in our factory; it may be fitted at our customer’s works providing they have access to a fitter & a surface grinder or milling machine.

 
VIDEO
MOTORISED MACHINE OPTIONS: Multi Notch Specimens

 
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