GB2445190A

GB2445190A - Subtractive Prototyping Machine

Info

Publication number: GB2445190A
Application number: GB0626047A
Authority: GB
Inventors: Joshua Nicholas George Reid
Original assignee: Individual
Current assignee: Individual
Priority date: 2006-12-30
Filing date: 2006-12-30
Publication date: 2008-07-02
Also published as: GB0626047D0

Abstract

A computer controlled subtractive prototyping machine comprising: a rotary Cutting Tool (1) which has a horizontal axis of rotation and is movable on a vertical linear axis and a horizontal linear axis that is parallel to its axis of rotation, further comprising a Rotary table (3) which is movable on one horizontal linear axis that is perpendicular to the other two axes and is rotatable on one vertical rotary axis, to which Rotary Table (3) Work (8) may be secured.

Description

Subtractive Prototyping machine Refer to Fig 1 The invention relates to

a computer controlled subtractive prototyping machine compnsing: a rotary Cutting Tool (1) which has a horizontal axis of rotation and is movable on a vertical linear axis and a horizontal linear axis that is parallel to its axis of rotation, further comprising a Rotary table (3) which is movable on one horizontal linear axis that is perpendicular to the other two axes and is rotatable on one vertical rotary axis, to which Rotary Table (3) Work Piece (8) may be secured.

The benefit of the configuration is that the two axes of translation that are used the most when material is cut from the work piece are horizontal and hence require the least possible work to move since no gravity forcez apply.

Refer to Fig 2,3 &4 Ills an object of the invention to allow the cutting of complex shapes requiring multiple axes of rotation is the simplest manner possible.

To this end the following embodiment is preterred: a rotary Cutting lool (1) which is movable on two linear axes, a Rotary table (3) movable on one linear axis and rotatable on one rotary axis, and a Work Assembly (5) that comprises a Work Piece (8) that is secured to a Work Attachment Plate (2).

The Work Assembly (5) may be connected to the Rotary Table (3) in two configurations. In the first the Work Assembly (5) is connected to the Rotary Table (3) such that if is positioned in a known and repeatable location, in the second configuration the Work Assembly (5) is connected to the perpendicular Angle Plate (4) which is connected to the rotary table (3) such that it is positioned in a known and

repeatable location.

In this way the Work Piece (8) may be cut with the tool pointing parallel to the plane of the Work Attachment Plate (2) in the first configuration, and the same Work Piece (8) may be remounted as described in the second configuration to allow cutting with the tool pointing perpendicular to the plane of the Work Attachment Plate (2).

This System creates allows the 4 axis machine described to create cuts that would only be possible on 5 axis machines.

Refer to Fig 5 The preferred embodiment comprises: a Main Frame Assembly (9) which may rest on the ground, a desk or similar surface, a Cross Frame Assembly (10) which is connected to the Main Fame Assembly (9) by way of horizontal guides such that it can translate on along a horizontal axis, a Vertical Axis Assembly (1 1) that is connected to the Main frame Assembly (9) by way of vertical guides and a Tool Assembly (12) that is connected to the Vertical Axis Assembly (11) by way of horizontal guides such that it may translate horizontally, and further comprising a Rotary Table (3) that is connected to the Cross Frame Assembly (10) such that t rnoy rotate about a vertical axis.

In the preferred embodiment a Tail Stock (13) is attached to the Cross Frame Assembly (10) and is rotatable about an axis coincident with the axis of the rotary bed, to which Tail Stock (13) may be attached a means of pulling the Work (14) clear of the cutting tool if the Work becomes severed.

Refer to Figs 6 & 7 It is preferred that the Work (14) is pulled clear of the by the Elastic Cords (15) that are attached to the Work (14) at one end via a tension able strap or similar and attached to the Tail Stock (13) at the other end, which Elastic Cords (15) are attached under tension such that the Work (14) is pulled clear if severed during the cutting process.

This allows a full and completely finished piece of Work (14) to be cut away from the work piece, without damage to the Work (14) produced or to the machine.

Refer to Fig S In the preferred embodiment the Cross Frame Guiding Means (16) connecting the Main Frame Assembly (9) to the Cross Frame Assembly (10) ore located at the upper and lower ends of the Cross Frame Assembly (10). This creates the most stable structure and minimises forces and maximises stiffness. It is preferred that the upper Cross Frame Guiding Means be shorter in length than the lower Cross Frame Guiding Means. This uses less material and provides a more compact overall assembly. It is preferred that the guiding means is provided by cylindncai guide rods and bushings.

In the preferred embodiment the lower guide rod is attached to the Cross Frame Assembly (10) and runs in bushings attached to the Main Frame Assembly (9) and a bushing is attached at the upper end of the Cross frame Assembly (10) which runs on a rod attached to the Main Frame Assembly (9). In this manner the guiding means may be easily covered from dust and finger traps may be prevented.

In the preferred embodiment a means is provided for measuring the length of the cutting too! attached to the machine. In the preferred embodiment ths is provided by means of a switch attached to the Cross Frame Assembly (10) in the location indicated at arrow (16).

Refer to Fig 9 It is preferred that the Spindle (17)10 the end of which the rotary cutting tool is attached is at least similar in length to the radius of the Rotary Table (3) or longer. If is advantageous to support the spindle in a slim manner to allow machining of more complex shapes without interference of the spindle (17) with the Work. It is preferred that the Main Frame Assembly (9) is provided with a vertical slot (18) through which the spindle (17) projects. This allows isolation of the cutting space from noise and dust and allows the Main Frame Assembly (9) to be of increased strength.

In the preferred embodiment the lead screw (19) driving the Cross Frame Assembly (10) is located near the lower Cross Frame Assembly (10) guiding means. This makes for the lease offset between the cutting force at the tool and the driving torce at the lead screw. A further lead screw may be added close to the upper Cross Frame Assembly (10) guiding means to prevent slewing of the Cross Frame Assembly (10) between the guides.

Referto Fig 10 In the preferred embodiment the Cross Frame Assembly (10) is provided with a Hinged Door (21) which hinges rotate on a vertical axis. This allows the space in which the Work Piece is cut to be isolated from the user for safety and acoustic insulation. It is preferred that the Cross Frame Assembly (10) be provided with an electromagnet or mechanical lock to prevent opening of the door while the machine is in use.

Refer to Fig 11 In the preferred embodiment the Vertical AXS Assembly (ii) runs wfh bushrgs (25) on cylindrical guide rods (23&24) that are attached to the Main Frame Assembly. It is preferred that the height of the vertical axis assembly is controlled by means of a lead screw (26) that is rotated to move the vertical axis assembly up and down.

It is preferred that all the lead screws and the rotary bed are driven by step type motors.

Refer to Fig 12 In the preferred embodiment the Tool Assembly (12) is provided with bushings (27) that run on guides which form part of the Vertical Axis Assembly (11). It is preferred that the spindle (17) is located down the centre axis of a tube (28) and connected to the tube via bearings which are clamped at both ends of the tube. It is preferred that the spindle is driven by a belt located at the end away from the cutting tool which belt connects to an electric motor (30). In the preferred embodiment the Tool assembly is also provided with a lead screw nut (29) which is attached to the plates which from the rest of the Tool Assembly.

Figure 1 shows the rotary Cutting Tool (1) and Rotary Table (3) with a Work Piece (8) secured to it. The cutting tool may translate on a vertical axis and a horizontal one towards and away from the Rotary Table (3). The Rotary Table (3) may rotate about a vertical axis and fronslate along a horizontal linear axis that is perpendicular to the axis of the tools translation.

Figure 2 shows the Work Piece (8) configured so that the rotary axis of the Cutting Tool (1) is perpendicular to the plane of the Work Attachment Plate (2), some material is shown cut away from the Work Piece by way of example.

Figure 3 shows the Work Piece (8) configured so that the rotary axis of the cutting tool is parallel to the plane of the Work Attachment Plate (2), some material is shown cut away from the Work Piece by way of example.

Figure 4 shows the Work Piece (8) configured so that the rotary axis of the cutting tool is parallel to the plane of the Work Attachment Plate (2), some further material is shown cut away from the Work Piece by way of example.

Figure 5 shows the overall assembly of the preferred embodiment of the present invention a prototyping machine. This includes the Main Frame Assembly (9), the Cross Frame Assembly (10), the Vertical Axis Assembly (11) to which is connected the Tool Assembly (12). Also show in the Rotary Table (3) that is connected to the Cross Frame Assembly (10).

Figure 6 shows the overall assembly of the preferred embodiment of the protolyping and model making machine with the Work (14) attached to the tail stock (13) in a situation where the Work (14) may be severed from the Work Piece (8) and pulled clear by the Elastic cords (15).

Figure? shows the Work (14) pulled clear of the Work Piece (8) by the Elastic Cords (15).

Figure 8 shows the positioning of the guiding means that connects the Main Frame Assembly (9) to the Cross Frame Assembly (10) and also shows the preferred location of the tool zeroing or offset measuring switch.

Figure 9 shows the overall assembly and illustrates how the Spindle (17) projects through a vertical slot (18) in the Main Frame Assembly (9).

Figure 10 shows the door (21) that isolates the work space from the user, and the door lock (22) that prevents the door from being opened under certain conditions of use.

Figure 1 shows the preferred embodiment in which the Vertical Axis Assembly (11) runs up and down using bushings (25) on cylindrical guide rods (23&24). Also illustrates the lead screw (26).

Figure 12 shows the preferred embodiment of the Tool Assembly (12) that is provided with bushings (27), a spindle (Ii), a tube (28) an electric motor (30) and a lead screw nut (29).

Figure 13 shows the preferred embodiment of the Tool Assemb'y sitting within the Vertical Axis Assembly.

Figure 14 shows the preferred embodiment of the Cross Slide Assembly Figure 15 shows the preferred embodiment of the Cross Slide Assembly Figure 16 shows the preferred embodiment of the Main Frame Assembly Figure 17 shows the preferred embodiment of the Main Frame Assembly Figure 18 shows the preferred embodiment of the Prototyping and Manufacturing Machine with the Vertical Axis Assembly hidden from view.

Figure 19 shows the preferred embodiment of the Prototyping and Manufacturing Machine with the Vertical Axis Assembly hidden from view.

Claims

Claims A computer controlled subtractive prototyping machine

comprising: a rotary Cutting Tool (1) which has a horizontal axis of rotation and is movable on a vertical linear axis and a horizontal linear axis that is parallel to its axis of rotation, further comprising a Rotary table (3) which is movable on one horizontal linear axis that is perpendicular to the other two axes and is rotatable on one vertical rotary axis, to which Rotary Table (3) Work (8) may be secured.
2. A computer controlled subtractive prototyping machine according to claim comprising: a rotary Cutting Tool (1) which is movable on two linear axes, a Rotary table (3) movable on one linear axis and rotatable on one rotary axis. and a Work Assembly (5) that comprises a Work Piece (1) that is secured to a Work Attachment Plate (2), which Work Assembly (5) may be connected to a Rotary Table (3) such that it is positioned in a known and repeatable location, furthermore the work assembly (5) may be reassembled in a manner that connects if to an angle plate (4) which is connected to the rotary table (3) such that it is positioned in a known and

repeatable location.
3. A computer controlled subtractive prototyping machine according to any preceding claims, in which the Rotary Table (3) is connected to the Cross Slide Frame (6) which Cross Slide Frame (6) is restrained by linear guides.
4. A computer controlled subtractive protofyping machine according to any preceding claims, in which the Cross slide frame has attached to it a rotatable Tail Stock (7) that is attached to the end of the Angle Plate (4) such that the angle plate may rotate about the rotation axis of the Rotary

Table (3).
5. A computer controlled subtractive prototyping machine according to any preceding claims, in which a connection is made between the Tail Stock (7) and the Work Piece () such that the top part of the Work Piece (1) is pulled vertically upward if the said Work Piece (1) is severed into two distinct pieces during the cutting process.
6. A computer controlled subtractive prototyping machine according to any preceding claims, in which the free length of the Cutting Tool (1) is similar to the diameter of the Work Attachment Plate (2).
7. A computer controlled subtractive prototyping machine according to any preceding claims, in which the linear axes are driven by helical lead screws.
8. A computer controlled subtractive prototyping machine according to any preceding claims, in which the lead screws are driven by step motors.
9. A computer controlled subtractive prototvping mochine occoding to any preceding claims, characterised in that the connection between the Tail Stock and Work Piece is made by an elastic cord.
10. A computer controlled subtractive prototyping machine according to any of the preceding claims, that uses guide rods and bushings to provide linear guides and is charactensed in that the guides supporting the Cross Slide Frame (6) are of different lengths. the higher one being shorter in length.
11. A computer controlled subtractive prototyping machine according to any of the preceding claims, that uses a flexible drive to transmit power to rotate the cutting fool.
12. A computer controlled subtractive prototyping machine according to any of the preceding claims, that uses compressed air to rotate the cutting tool.