What matters should be paid attention to in the application and operation of high-precision engraving machine for sandwich knife die?

Matters needing attention in the operation of high-precision engraving machine for sandwich knife die

Sandwich die plate is composed of steel plate and rubber interlayer, which has the characteristics of soft-hard composite, easy delamination, rubber melting by heating, and extremely high requirements for machine tool positioning/Z-axis depth accuracy. The core of equipment operation control is to ensure uniform cutter height, prevent plate delamination, reduce cutter breakage and maintain micron-level engraving accuracy for a long time, and it is divided into six sections: preparation before starting, processing and operation process, cutter and technology, environmental electricity, daily maintenance and safety specification.

First, check the preparation before starting.

Machine Tool Accuracy and Transmission System Inspection

Perform three-axis return to the origin, and test the sensitivity and reliability of the limit and origin induction switch; Check that the screw rod and the linear guide rail are free of debris, fully lubricated, and prevent crawling and gap drift (the depth tolerance of the die is directly affected by the gap).

Check the radial runout of the spindle, and the high-precision machine runout control is ≤ 0.015mm; Clean the dust and metal debris in the taper hole and gland of the spindle ER chuck. The chuck must be replaced in time for deformation and wear.

Check the vacuum adsorption/fixture platform: regularly check the flatness of the workbench; There is no air leakage in the vacuum pipeline, and the vacuum pressure reaches the standard; The clamp pressure plate is stressed evenly to avoid local warping of the plate.

Incoming inspection of sandwich plate

The upper and lower steel plates of the plate are free from warping and bulging, and the composite bonding is firm, and the delaminated and degummed blanks are removed in advance; The surface of the plate is clean, free of iron filings and foreign objects, so as to prevent the uneven carving caused by padding.

The thickness of the plate is uniform, and the total thickness measured by sampling before batch processing is used as the Z-axis depth benchmark.

Program and origin check

Check DXF cutter line drawing and engraving program unit (mm) to avoid inch/mm confusion; It is necessary to simulate the cutting with no load, and observe whether the stroke collides with the machine, and whether there is any abnormality in the corner of the cutting path and the logic of cutting.

Unified use of the same benchmark to set the origin of the workpiece; It is forbidden to re-align the knife at will in mass production; After the first trial carving, measure the height and overall dimensions of the knife, and mass production can be carried out only after it is qualified.

Confirmation of cooling and dust removal system

Water-cooled spindle: the coolant level is sufficient and there is no impurity, so it is forbidden to use tap water (it is easy to scale and block the waterway); Air-cooled type cleaning spindle cooling fan.

The dust suction device is turned on in advance to ensure that metal chips and rubber dust are sucked away in time; Rubber crumbs are easy to stick to the knife and melt and paste on the knife edge.

Second, the key control of processing and operation process

Plate clamping requirements (the most important thing is to prevent delamination and uneven depth)

Sandwich board must be flat and stick to the workbench, and local suspended carving is strictly prohibited; Vacuum adsorption is sufficient, and auxiliary briquetting is added to large-area plates; Do not press the pressure plate on the cutting line processing area.

In case of plate displacement and local warping during processing, stop the machine immediately, and it is forbidden to continue carving, otherwise the knife die will be scrapped directly if its height is inconsistent.

Z-axis depth control

Sandwich cutter die requires high consistency of cutter depth, and it is forbidden to change Z-axis parameters frequently. After each plate change and tool change, you must try to cut and check the depth.

Slant knife or spiral knife is used for cutting, and vertical stabbing is prohibited; It is easy to impact the plate vertically, resulting in the separation of the steel plate from the rubber interlayer, edge collapse and broken knife.

Real-time monitoring of operation state

Keep an eye on abnormal sound and vibration of the spindle; Abnormal vibration means that the tool is overloaded, the plate is loose or the chuck is loose, so stop immediately.

Observe the cutting state: the rubber interlayer is easy to melt and stick to the cutter when heated. Once the cutter sticks, stop the machine in time to clean the cutter;

Mass production: every 2 ~ 3 pieces are processed, the tool height and overall dimensions are sampled, and the origin, tool wear and plate deformation are investigated in time when deviations are found.

When the machine tool is running, it is forbidden to open the protective door and reach into the processing area; The spindle must be suspended when observing the workpiece.

Overload continuous operation is prohibited.

High-precision spindle avoids long-term full-load continuous processing, timely and intermittently cools down to prevent depth error caused by thermal expansion of spindle; Strictly control the temperature fluctuation in the computer room in summer.

Three, tool selection and cutting process considerations (for sandwich composite plate characteristics)

Tool specification

Choose special cutter die milling cutter for cemented carbide; If the blade is worn and broken, it should be replaced immediately. Blunt cutting will squeeze the rubber interlayer, produce a lot of burrs and uneven edge.

The tool suspension is as short as possible, and the longer the suspension, the greater the vibration and the worse the accuracy; The handle is fully loaded into the chuck to ensure the clamping rigidity.

Cutting parameter adaptation

Reasonable matching spindle speed, feed speed and cutting depth of each layer; Too fast parameters are easy to break the knife and the plate is layered; When the parameters are too low and the friction temperature rises too high, the rubber melts and sticks.

Layered milling is preferred, and it is not recommended to cut through the whole plate at one time to reduce cutting impact and protect the bonding structure of composite layer.

Chip removal guarantee

Metal chips+rubber mixed chips are easily wound around the cutter, and the dust suction port is aimed at the cutting area; If necessary, the cleaning of cutter winding waste shall be suspended periodically.

Four, electrical, environmental and grounding requirements (to ensure high precision and stable operation)

Power supply environment

The equipment independently stabilizes the power supply, avoiding sharing the circuit with welding machines and high-power equipment, and preventing step loss and size drift caused by voltage fluctuation and electromagnetic interference; Do a good job of reliable grounding and eliminate electrostatic interference.

Workshop environment

The ambient temperature is suggested to be 20 ~ 28℃. The sharp change of temperature will cause the screw rod and worktable of machine tool to expand when heated and contract when cooled, which will affect the engraving accuracy. Avoid direct sunlight on the machine bed.

Keep it dry to prevent the electrical control cabinet and spindle from getting wet; Clean up the dust in time, rubber dust is sticky, and it will accelerate the wear when it enters the guide rail and screw rod.

Five, daily and periodic maintenance points

After daily shutdown

Clean the metal chips and rubber dust on the workbench, guide rail and screw rod; Purge the spindle and shield with an air gun; Clean up the waste of the vacuum bucket; Check the chuck for rust and impurities.

Shutdown according to specifications: first stop the spindle → program reset → turn off the control system → cut off the main power supply.

Periodic maintenance

Daily: supplement special lubricating oil for guide rail and screw rod;

Weekly: check the XY positioning accuracy of machine tool and the verticality of spindle; Clean the filter of water cooling tank;

Monthly: check the tension of synchronous belt and motor terminal; Clean the dust inside the control cabinet;

Long-term shutdown: the guide screw is coated with antirust oil, the tool is removed and stored, and the equipment is covered with dust cover.

Key points: rubber dust is easy to solidify after being attached for a long time, and must be thoroughly cleaned regularly to avoid the permanent decline of accuracy caused by entering the transmission pair.

Six, common risk ban

It is strictly prohibited to start engraving when the plate is not firmly adsorbed and suspended;

It is forbidden to loosen the tool and touch the tip of the tool when the spindle is running;

It is forbidden to directly and vertically impact sandwich composite plates;

It is forbidden to use severely worn tools to continue batch processing;

It is forbidden to modify the core system parameters such as machine tool driver subdivision and screw clearance compensation at will;

In case of machine collision and broken knife, it is necessary to return to zero again and check the accuracy before continuing production.