GRAFS SR series grinding machine is designed for sharpening knives used in printing, paper, metal processing, wood and recycling industry. The knife sharpening machine model SR can be supplied in 4 different grinding lengths: 1 200 mm, 1 800 mm, 2 100 mm and 2 400 mm.
The grinder has a number of improvements to achieve high-quality sharpening for many years of use. It is equipped with a rotating electromagnetic chuck, it is also possible to attach knives using special clamps on the other side of the table. Angle from 0 to 120 degrees. Proper cooling of the sharpened surfaces is ensured by a cooling system with a tank and magnetic coolant cleaner with rotating magnetic drum – model MS or paper filter PS (as an option).
Developed in our firm the special holding adapter allows for quick and easy removal and fastening of the grinding wheel with three clamping screws.
Our trolley is equipped with the best class rolling rollers (PWTR) which ensures quiet and smooth moving.
In addition, as standard, the grinder is equipped with a slide carriage speed control system (potentiometer and inverter).
The machine is perfect for sharpening special purpose knives, where high precision grinding and rigidity are needed, e.g. guillotine knives for cutting paper. It is suitable also for chipper knives, granulator blades, veneer knives and all knives were heavy duty operation is needed.
The machine has all necessary electrical tests and European Union DECLARATION OF CONFIRMITY, build in Poland on European components.
Very easy to control the machine using the front panel.
The feed/drive speed of the carriage is set using the potentiometer knob. Simple switching on and off – the operation of the grinding wheel motor, electromagnet, trolley feed and cooling system – using switches.
GRAFS SR is equipped with the swiveling electromagnetic chuck with T channel plate on the other side of the chuck (for clamps mounting).
These two systems allows for secure fastening of the workpiece and precise grinding angle setting in the range from +-120 degrees.
The electromagnetic chuck can be produced with “S” Pole or in standard version. Chuck has polarity from 5 mm up to 25 mm (depends from order) and with max force 120N/cm2. Chuck is easily controlled from the control panel.
We help to choose the best solution for specific knives.
We provide individually tailored clamping systems for various knives.
We help to choose the most appropriate version for the convenience of our customers.
FIXING BOOK KNIVES: Attaching the knives to the paper cutters must be very precise. We have developed a special bar that keeps the knives in place. Thanks to this, each sharpening runs in a straight line and is repeatable.
The positioning bar can be easily moved up and down. Made of aluminum ensure safe operation.
FIXING CHIPPER KNIVES / RECYCLING BLADES: Attaching chipper knives or recycling blades sometimes requires mounting using special brackets. It is very important to sharpen each pair or set of knives equally. Uneven processing of material from each knife may result in improper operation of the mill or chipper. We provide a variety of solutions depending on the requirements of our clients. Even very short knives arranged in series can be precisely adjusted.
The machine is equipped with an inverter to adjust the carriage speed from 1 to 12 m/min.
All electronic components are made of high-quality materials from proven manufacturers (mainly Schneider)
EFFICIENT AND SAFE WORK
The grinder has covers to prevent excessive release of coolant dust during grinding. The amount of coolant fed to the machine by pump can be freely adjusted. Collant distributor in carriage is made of inox. The whole carriage can be manually positioned over the workpiece, which prevents the abrasive wheel from accidential hitting the workpiece. Machine has fast drive of main motor up / down by stepper motor, and slow approach by hand wheel. Steering by hand wheel can be also possible during work of the machine.
Our 24V safe LED lighting makes your work visible and safe. All our SR models come standard with a professional lamp.
The machine’s grinding wheel motor is manufactured in one of the oldest polish company: CELMA Inducta. Motor is additionally reinforced by GRAFS and is equipped with special spindle bearings with the elimination of axial play. Is also equipped with a special holder / adapter for quick mounting of the grinding wheel with three clamping screws. The grinding wheel can be changed in 1 minute. In SR model motor is available in several power variants: 5.5 kW, 7.5 kW, 11 kW.
Grinding Wheel motor can be produced in option with stable RPM (1450 RPM) or with changeable RPM, smooth regulation by potentiometer and inverter in range 1000 – 2800 RPM.
Specially designed holder / adapter allows for mounting different types of grinding wheels with just three locking screws. There is posiblility of fixing: ringwheels, segmental heads, diamond and CBN wheels (diameter from 150 mm up to 250 mm).
We developed our carriage for as convinient grinding wheel exchange as posiible. The space needed for exchange the grinding wheel is enough for fastening even big 250 mm segmental grinding heads.
With our system of the grinding motor sledge fast drive, exchange of the grinding wheel takes around 1 minute!
TRADITIONAL SOLUTIONS IN MODERN WAY
Our Focus is to manufacture machines which will work many years without any mechanical interference of the owner. We provide it by well known and tested solutions:
MAIN MOTOR SLEDGES
The grinding wheel motor’s sledge are driving on specially machined bronze guides. This solution allows for efficient and long life usage. The sledges are also positioned by regulated lubricated left and right steel guide. Even after many years of working the play on sledges can be easily eliminated.
The carriage’s driving system consists of two precisely machined steel guides covered with hardened strips of appropriate hardness.
High-strength PWTR rolling rollers (mounted in a trolley) move along the strips. This solution is more durable than standard linear systems used in CNC machines.
In each of our SR models, we have the ability to easily adjust the angle of the grinding wheel motor in the range of 0-5 degrees.
When we grind knives, the motor is set to about 2 degrees, but sometimes when there is need to grind flat surfaces – it’s easy with our adjustable mechanism.
In our SR model as a standard equipment are precise scales.
In case of need to regrind wider objects it is possible to regulate position whole carriage relative the trolley.
Thanks to this function in SR model there is possibility to regrind even knives with 360 mm width.
In the SR model, we can operate the feed of the grinding wheel motor to the cutter using a handwheel or, as an additional option, we can use a mechanical feed system on the so-called ratchet.
Stemless induction limit switches are responsible for changing the direction of travel of the trolley. Emergency limit switches located closer to the center of the stroller provide additional protection.
The machining coolant filtration module developed and built in our company consists of a magnetic separator MS model, with rotating magnetic drum (for removing magnetic spoil), mobile tank of capacity 150L and coolant pump with efficiency 60L/min.
Another option is PS paper band filter, which is dedicated fol filtration non magnetic materials like dust from grinding wheel or carbides. Filter works in automatic mode. When the dirty coolant reach special level then sensor will start paper band rolling.
The combination of both filters MS+PS, gives a high level of coolant purity which translates into quality and speed of sharpening process.
It is dedicated when sharpening knives for paper cutters and three knife trimmers when carbides are regrinded.
The machine carriage can be manually positioned over the knife, which allows for secure positioning of the grinding wheel disc relative to the workpiece. Thanks to the possibility of sliding the carriage relative to the trolley in Y axis, it is also possible to sharpen / grind objects or knives of larger widths (up to 360 mm).
Constructed of welded steel plates with a thickness of 20 mm. The trolley moves on 4 PWTR rollers with a diameter of 62mm (including 1 on an adjustable eccentric) for precise adjustment of the position of the rollers in relation to the guides. Additionally, on one of the guides, 2 internal fixed rollers and 2 external adjustable rollers are used to guide the trolley evenly in relation to the base.
The machine base is made of electro welded steel sheets (10mm) with appropriate ribs, in cell design – which makes the whole structure extremely stable. The rigid structure helps to avoid any vibrations or deflections during machining. The base is available in several lengths enabling the grinding range: 1200 mm, 1800 mm, 2100 mm, 2400 mm.
As a carriage running system, there are two steel guides equipped with hardened strips of appropriate hardness. High-strength PWTR rollers move on the straps. This solution is more durable than standard linear systems used in CNC machines.
