Patent Description:
Many products today contains at least one component that has been manufactured by machining. All the way from the body of a smartphone to an airplane containing thousands of machined components. The complexity of these products and components are constantly increasing. In addition, there is an increasing demand for higher and higher tolerances.

Traditional ways of manufacturing these products are by using either vertical milling machines where a workpiece is machined by a tool from above, or horizontal milling machines where the tool is working from the side. There is however need for improved solutions for machining, with higher precision and improved handling of the removed material.

Patent document <CIT> discloses a machining device comprising:.

It is an object of the invention to at least partly overcome one or more of the above-identified limitations of the prior art. In particular, it is an object to provide an improved machining device and method thereof for machining workpieces with an improved precision.

It has been realized that by having the cutting tool working from below an effective removal of chips cut from the workpiece is achieved. Further, the proposed distribution of the degrees of freedom in the machining device allows for a more stable machining device which results in improved precision.

According to a first aspect, it is provided a machining device comprising, a trunnion table adapted to hold a workpiece and arranged to pivot around a pivot axis by means of a pivoting motor, wherein the pivot axis is parallel to a horizontal plane, a spindle adapted to hold a cutting tool directed upwards and arranged to be moved in a plane parallel to the horizontal plane by a spindle transporting device, and a trunnion table transporting device adapted to vertically transport the trunnion table towards and away from the cutting tool, such that in a cutting state, chips cut from the workpiece is removed from the workpiece by gravity.

The trunnion table may be adapted to hold the workpiece in relation to the cutting tool such that in the cutting state, chips cut from the workpiece by the cutting tool is removed from the workpiece by gravity.

By the wording "cutting state" it is hereby meant a state in which the cutting tool is processing the workpiece.

Relative spatial terms such as "horizontal", "vertical", "upwards", "side" and "top" are used to refer to locations or directions within a frame of reference of the machining device. In particular, "top", "upwards" and "vertical" may be understood in relation to a bottom-up direction of the machining device (i.e. a direction from the trunnion table transporting device to the trunnion table), or equivalently a normal direction to a plane ground. Put differently, the bottom-up direction may be opposite to gravity. Correspondingly, the terms "horizontal", "beside" and "side" may be understood as locations or orientations in relation to / along the plane ground. By the wording "upwards" it is hereby meant a direction having a component in the bottom-up direction, i.e. opposite to gravity.

The spindle may be interpreted as a device which can hold and rotate the cutting tool. The cutting tool may for instance be a milling tool.

Having the vertical movement in the trunnion table means that it can be separated from the horizontal movements of the spindle. This may be advantageous in that forces created in the machining device from moving one of the parts does not affect the other. Put differently, the spindle for instance, can be moved along one direction in the horizontal plane without causing the workpiece on the trunnion table to vibrate due to the forces created by the movement. Thus, higher precision can be achieved in the machining process.

The machining device may further comprise a workpiece table rotatably connected to the trunnion table and adapted to hold the workpiece. The workpiece table may be arranged to rotate around a rotational axis. Said rotational axis may be orthogonal to the pivot axis.

An advantage of having the workpiece table which may rotate is that the workpiece can be rotated so that the cutting tool can reach all sides of the workpiece. Further, the workpiece may be rotated at high speeds so that turning can be performed by the machining device.

The machining device may comprise an additional workpiece table rotatably connected to the trunnion table and adapted to hold an additional workpiece. The additional workpiece table may be arranged to rotate around an additional rotational axis. The additional rotational axis may be orthogonal to the pivot axis. An advantage of having an additional workpiece table is that two workpieces can be machined at the same time. Alternatively, two workpieces can be loaded into the machining device at the same time and then be machined after one another.

The machining device may further comprise an additional spindle. The additional spindle may be adapted to hold an additional cutting tool directed upwards and arranged to be moved in the plane parallel to the horizontal plane by the spindle transporting device. Having an additional spindle may be advantageous in that two identical workpieces can be machined at the same time. Alternatively, the two spindles may machine one workpiece simultaneously.

The machining device may further comprise a base support structure, a side support structure, and a top connecting structure. The side support structure may be connected at a first end to the base support structure. The side support structure may be connected at a second end to the top connecting structure. The trunnion table transporting device may be connected to the side supporting structure. The spindle transporting device may be connected to the base support structure. Having the spindle transporting device connected to the base support structure can be an advantage in that the forces created when moving the spindle transporting device is picked up by the base support structure and not affecting the rest of the machining device, such as the trunnion table on which the workpiece is suspended. Similarly, having the trunnion table transporting device connected to the side supporting structure means that the vertical movements of the trunnion table doesn't affect the spindle.

The trunnion table transporting device may be connected to the side supporting structure at two opposite ends, such that the trunnion table is supported by the trunnion table transporting device at two opposite ends. Put differently, the trunnion table may be attached at two points opposite to each other along the pivot axis. An advantage of this may be that the trunnion table, on which the workpiece is attached, is much more stable as opposed to having a trunnion table attached in only one end. The stability may be important for the precision of the machining device.

The side support structure may comprise at least one opening for loading and/or unloading the workpiece horizontally.

The top connecting structure may comprise an opening arranged above the trunnion table for loading and/or unloading the workpiece vertically.

An advantage of loading the workpiece vertically is that transporting devices may run above the top connecting structure, thereby making it possible to reduce foot print in a production facility. The transporting devices may transport workpieces to and/or from the machining device.

The spindle may be movably arranged on the spindle transporting device along a first direction by means of a first motor. The spindle transporting device may be movably arranged on the base support structure along a second direction by means of a second motor. The first and second motor may be the same motor. The first direction and the second direction may be parallel to the horizontal plane. The first direction may be orthogonal to the second direction.

The spindle transporting device may move along rails attached to the base support structure.

The machining device may further comprise a chip conveyor arranged below the spindle for transporting chips away from the machining device.

By the wording "chips" it is hereby meant any material that is removed from the workpiece by the cutting tool.

The pivot axis may be parallel to the first direction. An advantage of which may be that movements of the spindle along the first direction has a minimal effect on the pivoting of the trunnion table.

According to a second aspect, it is provided a method for machining a workpiece using a machining device comprising a trunnion table holding the workpiece and a spindle holding a cutting tool directed upwards. The method comprises machining the workpiece from below by applying the cutting tool to the workpiece by, moving the spindle in a horizontal plane along a first and a second direction, wherein the first direction is orthogonal to the second direction, moving the trunnion table vertically thereby moving the workpiece, tilting the workpiece by pivoting the trunnion table around a pivot axis, wherein the pivot axis is parallel to the first direction.

The method may further comprise attaching the workpiece to the trunnion table.

The machining device may further comprise a workpiece table adapted to rotate around a rotational axis of itself and attached to the trunnion table. The workpiece may be attached to the workpiece table. The method may further comprise rotating the workpiece around the rotational axis of the workpiece table, wherein the rotational axis may be orthogonal to the pivot axis.

According to a third aspect, it is provided a non-transitory computer-readable storage medium having stored thereon program code portions for implementing the method according to the second aspect when executed on a device having processing capabilities.

The same features and advantages described with respect to one aspect are applicable to the other aspects unless explicitly stated otherwise.

The figures should not be considered limiting; instead they are used for explaining and understanding.

<FIG> is, by way of example, an illustration of a machining device <NUM> in cross-sectional view. It is noted that the machining device as illustrated in any of the <FIG> is to be seen as examples for illustrative purposes. The scales and shapes of the different parts may not reflect an actual machining device.

The machining device <NUM> may comprise a trunnion table <NUM>. The trunnion table <NUM> may be adapted to hold a workpiece <NUM>. Put differently, the workpiece <NUM> may be fixed to the trunnion table <NUM>. The workpiece <NUM> may be attached to the trunnion table <NUM> by hydraulics or any other suitable means for attaching a workpiece in a machining device which can be readily understood by the skilled person. The workpiece <NUM> may for instance be a piece of metal which is to be machined, for example by turning, milling or drilling. The trunnion table <NUM> may be arranged to pivot around an pivot axis <NUM>. Thus, also the workpiece <NUM>, which is fixedly arranged on the trunnion table <NUM>, may be pivoted. The trunnion table <NUM> can be said to have a first degree of freedom, i.e. the pivoting motion. The pivoting motion of the trunnion table <NUM> may be done by means of a pivoting motor. The pivot axis <NUM> may be parallel to a horizontal plane. For reference, the horizontal plane may be the plane spanned by the x- and y-axis. The pivot axis <NUM> may be parallel to the y-axis.

As illustrated herein, the trunnion table <NUM> may be attached at two ends opposite to each other along the pivot axis <NUM>. Alternatively, the trunnion table <NUM> can be attached to only one end. Further, the area where the workpiece <NUM> is attached to the trunnion table <NUM> may have an offset from the pivot axis <NUM>, such that a central section of the workpiece <NUM> can coincide with the pivot axis <NUM>. The offset of the trunnion table <NUM> may vary depending on the size of the workpiece <NUM>. For instance, the offset may be such that the center of gravity of the trunnion table <NUM> and the workpiece <NUM> together is close to the pivot axis. Thus, the trunnion table <NUM> with the workpiece <NUM> attached can pivot in a more effective and stable way and requiring less force by the pivot motor.

The machining device <NUM> may further comprise a spindle <NUM>. The spindle <NUM> may be adapted to hold a cutting tool <NUM>. The spindle <NUM> may rotate the cutting tool <NUM> such that milling or drilling can be performed. The spindle <NUM> may be arranged to hold the cutting tool <NUM> directed upwards, i.e. in the direction of the z-axis as herein illustrated. Put differently, the spindle <NUM> is arranged to machine the workpiece <NUM> from below, as opposed to the traditional way of vertical machining where the spindle is arranged above the workpiece. Having the spindle <NUM> working from below allows for an effective removal of chips <NUM> cut from the workpiece <NUM>, which is further discussed in connection to <FIG> and <FIG> when the machining device <NUM> is in a cutting state.

The spindle <NUM> can be arranged to be moved in a plane parallel to the horizontal plane by a spindle transporting device <NUM>. Thus, the spindle <NUM> can be said to have a second and a third degree of freedom. The spindle transporting device <NUM> is further discussed in connection to <FIG>.

The machining device <NUM> may further comprise a trunnion table transporting device 128a, 128b. The trunnion table transporting device 128a, 128b may be adapted to vertically transport the trunnion table <NUM> towards and away from the cutting tool <NUM>. Herein, the trunnion table transporting device 128a, 128b is illustrated as two rails on either side of the trunnion table <NUM> and transporting the trunnion table along the z-axis. The trunnion table transporting device 128a, 128b can be said to provide the trunnion table <NUM> with a fourth degree of freedom.

The machining device <NUM> as discussed so far thus have four degrees of freedom and may therefore be capable of performing <NUM>-axis machining. However, as illustrated in <FIG>. the machining device <NUM> may further comprise a workpiece table <NUM>. The workpiece table <NUM> may be rotatably connected to the trunnion table <NUM> and adapted to hold the workpiece <NUM>. The workpiece table <NUM> may be rotated by means of a rotational motor. The workpiece <NUM> may be attached to the workpiece table <NUM> by use of hydraulics. In other words, the workpiece <NUM> may be fixed to the workpiece table <NUM>. The workpiece table <NUM> may be arranged to rotate around a rotational axis <NUM>. The rotational axis <NUM> may be a normal axis to the workpiece table <NUM>. Being a normal axis to the workpiece table <NUM> may here mean being normal to a surface of the workpiece table <NUM> on which the workpiece <NUM> is held. The rotational axis <NUM> may be orthogonal to the pivot axis <NUM>. Thus, the rotational axis <NUM> may pivot around the pivot axis <NUM> together with the trunnion table <NUM>. The workpiece table <NUM> can be said to give the machining device <NUM> a fifth degree of freedom, thus allowing the machining device <NUM> to perform <NUM>-axis machining. The workpiece table <NUM> may rotate the workpiece <NUM> such that the cutting tool <NUM> can reach all points of the workpiece <NUM>. Further, the workpiece table <NUM> may rotate the workpiece at such high rotational speeds that turning can be performed by the machining device <NUM>.

The machining device <NUM> may comprise a base support structure <NUM>. The base support structure <NUM> may be any structure giving support to the machining device <NUM> from below. For instance it may be a machining device floor, or simply attachments for attaching the machining device <NUM> to a factory floor. The machining device <NUM> may further comprise a side support structure <NUM>. The side support structure <NUM> may be connected at a first end to the base support structure <NUM>. As one example, the side support structure <NUM> may be a single enclosed body. As another example, the side support structure may comprise one or more pillars. For example, four pillars arranged in four corners of the machining device <NUM>. The machining device may further comprise a top connecting structure <NUM>. The side support structure <NUM> may be connected at a second end to the top connecting structure <NUM>. The top connecting structure <NUM> may connect the side support structure <NUM> and giving the machining device additional stability. The top connecting structure <NUM> may be a single enclosed body. Alternatively, the top connecting structure <NUM> may comprise one or more beams connecting the side support structure <NUM>. In the exemplifying case of the support structure <NUM> comprising four pillars, the top connecting structure <NUM> may comprise four beams which pairwise connects the four beams.

The trunnion table transporting device 128a, 128b may be connected to the side support structure <NUM>. The spindle transporting device may be connected to the base support structure <NUM>. The spindle transporting device <NUM> may move along rails 124a, 124b attached to the base support structure <NUM>.

The trunnion table transporting device 128a, 128b may be connected to the side support structure <NUM> at two opposite ends. In other words, the trunnion table <NUM> may be supported by the trunnion table transporting device 128a, 128b at two opposite ends.

In the illustration of <FIG>, the machining device <NUM> may be referred to as being in an idle state. In this state, the workpiece <NUM> is loaded in the machining device <NUM>, but the cutting tool is currently not in contact with the workpiece.

<FIG> illustrates the machining device <NUM> in a cutting state. In this illustration, the trunnion table transporting device 128a, 128b has transported the workpiece <NUM> towards the cutting tool <NUM> such that the cutting tool <NUM> can machine the workpiece <NUM>. Chips <NUM> that are created from material being removed from the workpiece <NUM> can fall away from the workpiece by gravity due to the spindle <NUM> working from below the workpiece <NUM>. During the cutting state, the cutting tool <NUM> is below (in relation to the z-axis) a point of the workpiece <NUM> at which the cutting tool is in contact with. The machining device <NUM> may be arranged such that the cutting tool <NUM> always is below the point of the workpiece <NUM> at which the cutting tool <NUM> is in contact with during the cutting state. Removing the chips <NUM> from the workpiece <NUM> during the cutting state can improve the finish of the product. By the proposed solution the chips can be prevented from collecting in or on the workpiece during the cutting state. The machining device <NUM> may further comprise a chip conveyor <NUM> for transporting chips away from the machining device <NUM>. The chip conveyor <NUM> may be arranged below the spindle. The chip conveyor <NUM> may for instance be incorporated in the base support structure <NUM> or attached thereon. Alternatively, the chip conveyor <NUM> may comprise an opening in the base support structure <NUM> allowing the chips <NUM> to fall out from the machining device <NUM>. The chips <NUM> can also be removed by that the spindle transporting device <NUM> is provided with slanted surfaces.

<FIG> illustrates an alternative view of the machining device <NUM> in the cutting state. In this illustration, the trunnion table <NUM> has pivoted around the pivot axis <NUM> allowing the cutting tool <NUM> to reach points on a side of the workpiece <NUM>. It is noted that the trunnion table <NUM> may take any pivoted position around the pivot axis <NUM>, not just the two examples of <FIG> and <FIG>.

<FIG> illustrates, by way of example, the machining device <NUM> having an additional workpiece table <NUM> and an additional spindle <NUM>.

The additional workpiece table <NUM> may be rotatably connected to the trunnion table <NUM> and adapted to hold an additional workpiece <NUM>. The additional workpiece table <NUM> may be arranged to rotate around an additional rotational axis <NUM>. The additional rotational axis may be orthogonal to the pivot axis. As illustrated herein, the additional workpiece table <NUM> may be arranged beside the workpiece table <NUM>.

The additional spindle <NUM> may be adapted to hold an additional cutting tool <NUM> directed upwards. The additional spindle <NUM> may be arranged to be moved in the plane parallel to the horizontal plane by the spindle transporting device <NUM>. The two spindles <NUM>, <NUM> may be arranged on the spindle transporting device <NUM> with a fixed distance between them.

The machining device <NUM> as illustrated herein may be used to simultaneously machine two identical workpieces <NUM>, <NUM>. Alternatively, the machining device <NUM> may be used to machine one workpiece <NUM> using two spindles <NUM>, <NUM>. Alternatively, the machining device <NUM> may be used to machine two workpieces <NUM>, <NUM> using one spindle <NUM>.

<FIG> illustrates the machining device in a vertical loading state. An opening <NUM> may be provided in the top connecting structure <NUM>. The opening <NUM> may be provided above the trunnion table <NUM> for loading and/or unloading the workpiece <NUM> vertically. Put differently, the machining device <NUM> may be loaded and/or unloaded from above. In the vertical loading state, the trunnion table <NUM> may be pivoted so that the workpiece <NUM> can be accessed from above. Further, the trunnion table transporting device 128a, 128b can raise the trunnion table to a top position so that the workpiece <NUM> is easily accessible. The vertical loading state of the machining device <NUM> may be compatible with pallet changers moving above the machining device <NUM> for loading and/or unloading.

<FIG> illustrates the machining device in a horizontal loading state. The side support structure <NUM> may comprise at least one opening for loading and/or unloading the workpiece <NUM> horizontally. Put differently, the machining device <NUM> may be loaded and/or unloaded from the side. As an example, the side support structure <NUM> may be provided with openings at the two sides of the side support structure <NUM> where the trunnion table transporting device 128a, 128b is not attached.

In the horizontal loading state, the spindle transporting device <NUM> can move away from the opening from where the workpiece <NUM> is to be loaded or unloaded, thus allowing the workpiece <NUM> to be positioned at a height suitable for the loading/unloading. The horizontal loading state of the machining device <NUM> may be compatible with pallet changers for loading and/or unloading.

<FIG> illustrates the machining device <NUM> in a cross-sectional view from above, with an opening in the top connecting structure <NUM>. More specifically, <FIG> illustrates the spindle transporting device <NUM> from above. For illustrative purposes, the trunnion table <NUM> with the workpiece table <NUM> and the workpiece <NUM> is not included.

The spindle <NUM> may be movably arranged on the spindle transporting device <NUM> along a first direction <NUM>. The movement may be made by means of a first motor. The first motor may be a linear motor. The spindle <NUM> may move along a rail <NUM> on the spindle transporting device <NUM>.

The spindle transporting device <NUM> may be movably arranged on the base support structure <NUM> along a second direction <NUM>. The movement may be made by means of a second motor. The second motor may be a linear motor. Herein, the spindle transporting device <NUM> is illustrated as moving along two rails 124a, 124b on the base support section <NUM>. However, the number of rails may be one or more.

The first direction <NUM> and the second direction <NUM> may be parallel to the horizontal plane. Further, the first direction <NUM> may be orthogonal to the second direction <NUM>. The pivot axis <NUM> may be parallel to the first direction <NUM>.

<FIG> is a flow-chart illustrating a method <NUM> for machining a workpiece using a machining device. The machining device may comprise a trunnion table holding the workpiece and a spindle holding a cutting tool directed upwards. The method <NUM> comprises a plurality of steps. Below the different steps will be discussed in more detail. It is noted that the steps may be executed in any suitable order.

The workpiece may be attached S802 to the trunnion table.

The workpiece is machined S804 from below by applying the cutting tool to the workpiece.

The workpiece is machined by moving S806 the spindle in a horizontal plane along a first and a second direction. The first direction may be orthogonal to the second direction.

The workpiece is machined by moving S808 the trunnion table vertically thereby moving the workpiece.

The workpiece is machined by tilting S810 the workpiece by pivoting the trunnion table around a pivot axis. The pivot axis may be parallel to the first direction.

The machining device may further comprise a workpiece table adapted to rotate around a rotational axis of itself and attached to the trunnion table.

The workpiece may be attached S812 to the workpiece table.

The workpiece may be machined by rotating S814 the workpiece around the rotational axis of the workpiece table. The rotational axis may be orthogonal to the pivot axis.

Even though described in a certain order, the different steps may also be performed in other orders, as well as multiple times. For instance, moving the spindle, moving the trunnion table, tilting the workpiece and rotating the workpiece may be done simultaneously.

Claim 1:
A machining device (<NUM>) comprising:
a trunnion table (<NUM>) adapted to hold a workpiece (<NUM>) and arranged to pivot around a pivot axis (<NUM>) by means of a pivoting motor, wherein the pivot axis (<NUM>) is parallel to a horizontal plane,
a spindle (<NUM>) adapted to hold a cutting tool (<NUM>) directed upwards and arranged to be moved in a plane parallel to the horizontal plane by a spindle transporting device (<NUM>), and
a trunnion table transporting device (128a, 128b) adapted to vertically transport the trunnion table (<NUM>) towards and away from the cutting tool (<NUM>),
such that in a cutting state, chips (<NUM>) cut from the workpiece (<NUM>) is removed from the workpiece (<NUM>) by gravity.