GB2282899A - Numerically-controlled machinery - Google Patents

Abstract

Apparatus for cutting a two or three dimensional predetermined shape from a blank exploits a method of waveform generation in which a calculator (1) is programmed to create a sequence of output values, each value comprising the calculated result of a generator equation. A cutting tool (5) traces out the calculated result. <IMAGE>

Description

NUMERICALLY - CONTROLLED MACHINERY This invention relates to an apparatus and method for cutting two-dimensional or three-dimensional shapes from a blank.

It is known that a cutting tool may be controlled by electronic means which, in turn, is programmed to produce the appropriate control signals.

An object of this invention is to provide a means for generating control signals by which a great variety of two or three- dimensional shapes can be created with the minimum amount of software.

Accordingly the invention comprises cutting apparatus including: calculator means for receiving a set of input values which form the argument ' of a generator equation and for creating a sequence of output values, each output value comprising the calculated result of the generator equation corresponding to each input value; and cutting means for tracing out said calculated result.

Hence the shape to be cut out from a blank is dictated by the generator equation and the cutting means traces out a graph of input values versus output values.

The invention exploits a method of waveform generation which is described in detail in our co-pending European Application EP-A-509,713. Therein, certain generator equations e.g. an inverse uf a trigonometric function arc.cos(sin P), are referred to a "Portmanteau Functions".

Herein, a Portmanteau Function can be any generator equation.

Some embodiments of the invention will now be described, by way of example only, with reference to the drawings of which: Figure 1 is a representation in block diagram form of a first embodiment; Figure 2 is a representation in block diagram form of a second embodiment; Figure 3 is a perspective view of a surface profile.

In Figure 1 a calculator 1 receives inputs from an associated keypad 2 and has an output connected to a tool control module 3. The module 3 also receives an input signal from the keypad 2. An output from the tool control module 3 is connected to an activator 4 which is fitted with a cutting tool 5.

In operation, an operator types into the calculator 1 via the keypad 2 a Portmanteau Function having the general form; y=f(P) i.e. y is some function of P. Suppose in this specific example the operator types in: p2 2 + -l a2 b2 i.e. the equation for an ellipse. Next, the operator types in a prechosen set of values for P and the values of the constants a and b.

The calculator 1 is preprogrammed with the necessary algorithms to calculate a sequence of y values for each pre-chosen value of P in the set. The y values along with the corresponding P values are input to the control module 3 which converts this information into the appropriate drive signals for the actuator 4. Thus the cutting tool 5 scribes or cuts out the ellipse on an appropriate blank sheet of material.

In a second embodiment, the invention is extended to three dimensions so that surface profiling or the creation of three-dimensional objects can be carried out.

In Figure 2, a first calculator 6 receives a Portmanteau Function y = f(P) and a set of P values P=P1....Pn Pn and calculates and outputs the sequence of y values Y1.... Yn. A second calculator 7 receives a Portmanteau Function y'=f(P') and a set of PX values P=P.... P/n and calculates and outputs the sequence of yX y'1....Y'1. Ytn e Next the y and y/ values are multiplied together by a multiplier 8 and the resulting sequence of values Z.... .. Z is applied to the tool control module 9. The two sets of values P1.... Pn and P1 .... Ptn are applied to the two remaining inputs of the module 9. The module 9 converts the three sets of inputs into the appropriate signals for controlling an actuator 10 which in turn controls the motion of a cutting tool 11 in three dimensions.

In one specific case, let, y=l+sgn.(sinP), and y=l+sgn.(sinP), in which case z=(l+sgn.(sinP)).(l+sgn.(sinP)) Figure 3 shows a perspective view of the profile of a surface which would be cut by the tool 11 as governed by the above Portmanteau expressions for y and y.

Claims (2)

1 Cutting apparatus including: calculator means for receiving a set of input values which form the argument of a generator equation and for creating a sequence of output values, each output value comprising the calculated result of the generator equation corresponding to each input value; and cutting means for tracing out said calculated result.

2 Cutting apparatus substantially as hereinbefore described with reference to the drawings.