Patent Application
20190168534
This invention relates to a CNC (computer numerically controlled) marking device adapted for use in a CNC machine.
CNC (computer numerically controlled) machines are used to form complex parts that are machined in a single operation using more than one tool. The machine selects a tool from a bank of tools that are at its disposal. For example, the machine may select a milling tool to form a profile on a workpiece and then subsequently select a drill tool to form holes in that workpiece and substantially complete the part. Commonly the single operation is performed in a closed environment, which is furnished with cooling/lubricating fluids used to aid the machining.
Parts that are machined using a CNC machine often need to be traced. This may be, for example, to ensure batch identification should one part of a batch develop a fault. To trace such parts they are often marked with an identification code. This process is often completed using a marking machine that each part is placed into. However, the simple movement of each part from one machine to the next may result in damage to the part if it is dropped or accidently bumped into other objects. It is for this reason that CNC machines are able to perform more than one section of the machining process. Returning to the above example, a margin for error would be introduced to the machining operation if the milling was performed in a different machine to the drilling.
It is therefore desirable to mark each part as it is formed. However, as mentioned, the CNC machine environment is closed and contains fluid and debris.
EP1361960 describes a handheld marking device that may be used to mark a surface for permanent identification purposes. Such a device may therefore be used to mark each part formed by the CNC machine. This could be a manual or semi-automated, i.e. robotic, operation that takes place as each part is unloaded from the CNC machine and therefore, in some circumstances, eliminates the need for a static marking machine in which each part must be loaded. However, such an operation still requires transportation of the part from the CNC closed environment to an area accessible by the marking machine.
US2010/0275794 describes a CNC machine having a gantry on which is mounted tooling, to effect working on a workpiece mounted on a tooling table, and a carriage, holding a marking device. A marker controller operates the marking device to mark a workpiece with data derived from a CNC controller and from an HMI device. Such an arrangement is complicated but can be simplified.
It is an object of the present invention to address the problems identified above, or at least to mitigate their effects.
In accordance with the present invention there is provided CNC machine comprising: a holder for a workpiece to be machined; a tool array comprising one or more tools; a machining arm having a first connector and adapted to select and use one of said one or more tools to machine said workpiece; and a marking device having a second connector and positionable in said tool array and selectable by said machining arm by interengagement of said first and second connectors, wherein said marking device comprises: a housing; a marking head mounted in said housing, said marking head comprising a marking tip being moveable in a marking direction for marking said workpiece; a controller for controlling said marking pin; and a wireless communicator adapted to receive instructions from a transmitter unit, said instructions being passable to said controller to instruct said controller to control said movement of said marking tip.
Said wireless communicator may comprise a wireless communicator such as, for example, a Bluetooth® module. The wireless communicator may be further adapted to transmit data indicating the current or historic movement of said marking head and/or said marking tip.
The machine may further comprise a computer adapted to transmit said instructions to said wireless communicator. Said computer may be further adapted to receive said data indicating the current or historic movement of said marking head and/or said marking tip.
Said wireless communicator might be pneumatically or hydraulically driven through connection of the machining arm to the marking device and under the control of a controller of the CNC machine that controls said machining arm.
The marking device may further comprise a support frame on which said housing is mounted substantially enclosing said support frame, said frame providing a mount for said marking head and said controller. The housing may comprise a body, a base and a lid, wherein said base and said lid are fixable to said frame and said body is positionable between said base and said lid, so that fixation of said base and lid to said support frame clamps said body and forms said housing, which is preferably fluid-sealed.
The marking tip is preferably moved by electromagnetic means.
The marking device may include its own power source, which may be activated and deactivated by connection to said machining arm of the marking device.
The housing may also comprise a window through which said marking head and/or marking tip protrudes, a gaiter being connected between said marking head and said window to fluid-seal for said window.
Preferably, the marking head is also mounted for translational movement in a marking surface under the control of said controller, said marking surface being substantially orthogonal with respect to said marking direction.
The marking surface may be planar and said translational movement may be effected by a first motor and a second motor wherein said first motor is adapted to move said marking head in a first direction in said marking plane and said second motor is adapted to move said marking head in a second direction in said marking plane, wherein said first direction is substantially perpendicular to said second direction.
Said first and second motors may be fixed in the support frame and drive belts that slide a marking head mount in said first and second directions.
Alternatively, said marking surface may be cylindrical and said translational movement is effected by a first motor and a second motor. The first motor may be disposed on a tilting frame pivoted in the support frame, the first motor being arranged to tilt the tiling frame in a first direction with respect to the support frame, and the second motor may be mounted on a slide mount slidable by operation of the second motor in a second direction substantially orthogonal with respect to said first direction, the slide mount mounting said marking head.
The invention also provides a marking device suitable for use in a CNC machine as defined above, the marking device comprising: a marking head mounted in a housing of the device, said marking head comprising a marking tip being moveable in a marking direction for marking said workpiece; a controller for controlling said movement of said marking pin; and a wireless communicator adapted to receive instructions from a transmitter unit, said instructions being passable to said controller to instruct said controller to control said movement of said marking tip.
The marking head may be mounted for translational movement in a marking surface under the control of said controller, said marking surface being substantially orthogonal with respect to said marking direction. The device may further comprise an on-board power source to power the controller and drive said marking head. The marking device may further comprise a pneumatically operated switch adapted for operation by a pneumatic source of a CNC machine to connect said power source to and disconnect said power source from the controller and marking head.
The invention also provides a method of marking a workpiece in a CNC machine comprising: a holder for said workpiece; a machining arm adapted to select and use a tool to machine said workpiece; and a marking device selectable by said machining arm, said marking device comprising a marking head having a marking tip being movable in a marking direction under the control of a controller, and a wireless communicator connected to said controller; wherein said method comprises the steps of:
Said marking head may be movable in the marking device in a marking plane being substantially orthogonal with respect to said marking direction, the method further comprising the step of:
The method may further comprise the step of:
Step c) may further comprise activating a power source in the marking device. In which case, said activation of the power source may be effected pneumatically under the control of the CNC machine.
Said controller may receive instructions from a computer remote from said marking device outside of said CNC machine. The method may further comprise the steps of:
Optionally, step g) further comprises the steps of:
After checking the image, the computer may notify the CNC machine that the power source is to be deactivated.
These and other features, aspects, and advantages of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings, where:
The following description provides detailed examples of some embodiments of the present invention.
In
The machining arm 600 operates under the control of a CNC controller 700, located outside of the room but most likely hardwired to the arm by a line 710. Other supply lines (not shown) may connect to the machining arm to supply hydraulic power, pneumatic power or electrical power to the arm, and to a tool 622 connected to the arm.
A marking device 10 comprises one of the tools 622, in accordance with an embodiment of the present disclosure, which is selectable by the machining arm as and when required under the control of the CNC controller 700. It also has a corresponding second connector 624 for engagement with the first connector 650. As described below, the marking device may include an on-board power source that is activated when the device 10 is engaged by the arm 600. It also includes a wireless communicator (described further below) that is adapted to receive signals from, and optionally transmit signals to, an external controller 800, which may be a personal computer or other device having an antenna 810.
According to some embodiments of the present invention, the marking device 10 comprises a housing 12, which forms a, preferably, fluid-sealed environment. A fluid resistant housing is potentially satisfactory since tool arrays in CNC machines (where the marking device 10 might be stored when not in use) are generally isolated from the area of the machine where machining of the workpiece takes place and a hot wet environment pertains. Also, during use of the marking device, any fluid lubricant or cooling supply would likely be disengaged. Hence absolute fluid-sealing is not essential.
A first connector 14 is positioned at the top end of the marking device relative to a marking head 16 as used to mark the workpiece. The connector preferably comprises a collar 14a adapted to engage with a second connector (not shown) on the machining arm (not shown) of the CNC machine. The machining arm further comprises locking means positionable inside lugs 14b. The marking device is storable in the array of tools inside the CNC machine. A reveal 14c (optionally in the form of a cylindrical groove) in the connector is adapted to be engaged by a forked bracket on which the marking device is stored after disconnection from the shaft of the machining arm.
The marking head 16 of the marking device 10 is mounted inside the housing 12 and is moveable in a marking plane (x, y). Movement within the plane is effected by movement in a first direction x and a second direction y, the second direction y being substantially perpendicular to the first direction x. Movement in the first direction x is effected by a first motor 18 and movement in the second direction y is effected by a second motor 20.
The marking head comprises a marking tip 22, which is used to mark the workpiece. The head 16 projects from the housing 12 through a marking window 24. Marking is performed by moving the marking tip 22 in a marking direction z onto the workpiece using, for example, electromagnetic means such as a solenoid. Alternative means of moving the marking tip are described below. A power regulator 26 is also mounted inside the housing 12 and is used to supply electrical power to move the first and second motors 18, 20 and optionally the marking tip 22. The electrical power may be supplied by the machine arm or could, as described below, be supplied by an on-board power source such as a battery.
In some embodiments, the marking device also comprises a frame 28 positioned inside the housing to provide a support for the housing and a mount for the marking head, first and second motors and the power regulator 26. The frame may be of metal construction and may be of, but is not restricted to, a planar construction. The housing 12 comprises a base 30, a cylindrical body 32 and a lid 34. The base 30 and the lid 34 provide a clamp for the body 32 when the base and the lid are fixably attached to the frame 28. Suitable fixings may be, for example, bolts or screws 36. The clamping of the body 32 between the base and the lid provides a fluid-sealed housing. O-rings 38 provided at the junction between the base and the body, and the lid and the body enhance the fluid seal. A flexible gaiter (not shown) is attached between the window 24 and the marking head 16 so as to provide a fluid seal over the marking window region.
As mentioned above, the body may be cylindrical in shape wherein the combination of the frame and the clamping arrangement provides a strong rigid configuration. The frame provides a transfer of force from the marking tip as it impacts the workpiece to the machining arm.
Turning to
In some embodiments, the marking device comprises a controller 50 adapted to control the first and second motors to effect movement of the marking head. As used herein, a “controller” is something that directs or regulates something, such as, for example, a motor. A controller can be used in connection with software that directs the controller's function. A controller can include memory such as a random access memory chip. A controller can be a microcontroller (or MCU for microcontroller unit) that contains one or more CPU cores, and may include memory and programmable input/output peripherals or a similar programmable controller on a single integrated circuit, including a system on a chip or SoC, or state machine.
The controller may be a pre-programmed computer that is able to translate computer code data into a series of movement commands for the first and second motors. Furthermore, the controller controls the movement of the marking tip. In the example of the marking tip being movable using electromagnetic means, the controller may send a pulse signal to the power regulator, or direct to the electromagnetic means, to actuate the marking tip and therein punch the tip into the surface of the workpiece.
The marking device may also comprise a communicator 42, such as a wireless communicator (for example, a Bluetooth® module) for receiving and optionally transmitting data. The data primarily comprises instructions (e.g. the computer code) for the controller that are used to instruct the controller to move the first and second motors 18, 20 and the marking pin 22. The communicator 42 is shown to be placed proximal to the power source 40. However, the communicator 42 can be located anywhere inside the housing. The communicator 42 is connected to the controller using cabling (not shown) connected at terminals 52. However, it is understood that the controller and the communicator may be positioned on a single printed circuit board 54, or the like. In another embodiment, the controller 50 may comprise the communicator.
In a preferable embodiment of the marking device, the base 30 comprises a camera window 56. A camera 58 positioned inside the housing 12 so that a fluid seal is formed with the base 30. The camera is used to check the mark produced by the marking head.
The CNC machine arm may comprise a pneumatic supply which is switchable between an on and an off state by the machine. In some embodiments, the marking device comprises a pneumatically operated switch. In these embodiments, connection of the marking device to the machining arm completes a pneumatic circuit wherein the switching of the pneumatic supply operates the pneumatic switch between an on- and an off-state. The pneumatic switch is used to control the power source so the switch turns the marking device on or off. This feature serves a purpose of reducing battery consumption when the marking device is not marking the workpiece.
Alternatively, a Hall-effect reed switch (31—see
The advantage of the latter is that no pneumatic connection is required, which in some CNC machines might not be provided. Also, the switch is entirely located within the housing so it is protected from the environment within the CNC machine. A different switch, however, could be operated in other ways, for example by mechanical operation through the machine arm 600 being arranged to press the housing incorporating a mechanical switch against a stop on the table 640 to actuate and de-actuate the switch.
That is, the marking device may comprise a switch that is actuatable by movement of the machining arm after connection of the marking device to the machining arm, and de-actuatable by corresponding movement when marking of the workpiece has been completed and prior to return of the marking device to the tool array.
In
The pneumatic system may also be used to drive the marking tip. In this configuration, a switched valve, controllable by the controller, would be placed between the pneumatic supply and the marking tip. The supply may be taken from the pneumatic switch or directly from the first connector. The marking head, in this configuration, comprises a piston having a piston head movable in said piston and resiliently biased away from the workpiece. The marking tip is in turn connected to the piston so that on opening of the switched valve, the marking tip is pneumatically forced toward the workpiece and on closing of the switched valve, the marking tip retracts from the workpiece.
To create a mark on a workpiece, the CNC machine of any of the above embodiments performs the method of:
Steps a) and b) are performed by the CNC machine under its control (using its own controller, 700 in
Where a camera is included in the marking device 10, a step f) (before notifying the CNC machine that the marking operation has been completed) comprises: positioning the camera of the marking device over the mark made by the marking device 10 so as to obtain an image of the mark. This image may be communicated to the computer which is arranged to detect the image and ensure that it is readable and that what is read corresponds with what was intended.
It is to be understood that part of the reason for employing a marking controller and a marking head that is movable in the marking device in said marking plane is because CNC machines are not readily adapted to produce unique and variable movements at the touch of a button, or especially to move in a fashion to describe a unique and variable dot matrix code. Thus, the present invention requires only that the machining arm is held stationary with said marking plane held at an appropriate distance from, and substantially parallel to, a surface of the workpiece to be marked. Thereafter, the arrangement of the marks on the workpiece made by the marking pin is under the control of the marking controller in the marking device and/or the computer 800 in communication with it.
However, it may well be that such functionality may ultimately become readily available in CNC machines, in which event the marking head may be fixed in said marking device with the machining arm making the necessary movements, under the control of the CNC's controller, to trace the required pattern of movements for the marking device over the workpiece. Nevertheless, in many applications a simplified controller 50 and communicator will still be required because a solenoid actuated marking pin provides the cleanest and most accurate mark in the surface of the workpiece. In many instances, the workpiece will be a highly valued part in which additional stresses are to be avoided where necessary. A precisely weighted single punch to a precise depth ensures a minimum additional stress imposed on the workpiece.
Indeed, in its simplest form, the communicator could be a pneumatic connection where each pulse of air is sensed by the controller as an instruction to effect a punch once the CNC machine has moved the marking head to a desired position. In this arrangement, no external or separate computing is required, since the CNC machine is itself fully enabled. Other forms of communicator are envisaged, such as infra-red or a wi-fi connection, including Bluetooth®.
Until such time as CNC machines are rendered adaptable to move their machining arms in unique and varying patterns, a marking device with the full functionality described above will remain necessary. However, while the arrangement of
However, between the side walls 28a, b is pivoted, about journal axis 100, a tilting frame 102. Between arms 102a, b of the tilting frame 102 is fixed a first motor 18′ which has an armature (not visible) mounted around a first lead screw 104. One end of the first lead screw is fixed axially (with respect to the lead screw) in back wall 28c, so that when the first motor 18′ operates, it screws itself up and down lead screw 104 so as to tilt tilting frame 102 about its journal axis 100.
Independently, a second motor 20′ is likewise disposed around a second lead screw 106 mounted between the arms 102a, b of the tilting frame 102. Around the second motor 20′ is a slide mount 17′ which slides on rails 110 on a base 102c of the tilting frame 102. The slide mount 17′ carries the marking head 16′. When the second motor 20′ operates, it screws itself along the second lead screw 106 in the y direction, taking the marking head 16′ with it. Because the tilting frame pivots, however, the marking head moves in an arc when the first motor operates, so that the surface described by the marking pin when the motors operate is not planar but cylindrical. For most purposes, this is satisfactory.
Otherwise the marking device 10′ is essentially the same. It has a different first connector 14′, a simple on-off switch 111 that is manually operated and LED lights 112 that inform the user that the marking device is live and the state of the battery 40′. However, by employing the tilting arrangement smaller motors can be employed and so the tool has a smaller diameter. It can therefore be employed by more CNC machines.
Throughout the description and claims of this specification, the words “comprise” and “contain” and variations of them mean “including but not limited to,” and they are not intended to (and do not) exclude other components, integers or steps. Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.
Although the present invention has been described in considerable detail with reference to certain preferred embodiments, other embodiments are possible. The steps disclosed for the present methods, for example, are not intended to be limiting nor are they intended to indicate that each step is necessarily essential to the method, but instead are exemplary steps only. Therefore, the scope of the appended claims should not be limited to the description of preferred embodiments contained in this disclosure. All references cited herein are incorporated by reference in their entirety.
