Inexpensive CNC woodworker starts business

Low cost CNC woodworking machine accurately duplicates a CAD program in much less time than someone working by hand - an advantage which helped start up a business.

A CNC programmer started a successful new production woodworking business with an inexpensive but highly accurate and productive computerised numerical control (CNC) machine.

There is a substantial market niche for producing decorative wood carvings much faster and at higher levels of accuracy on CNC machines, but at a lower price.

Low cost CNC machines can accurately duplicate a computer aided design (CAD) program in much less time than someone working by hand, said UK Isel distributor, Micromech.

The then existing market for decorative wood carvings was characterised by cost and long lead-times, which restricted sales.

Making complicated pieces such as carved mouldings and friezes is a very slow process by hand, said Micromec h to manufacturingtalk.com.

The usual practice is to assign the first piece to a very experienced and highly paid craftsman.

The craftsman cuts the product out using hand and power tools.

Less experienced workers then duplicate the piece using a tracer.

One problem with this approach is that even the most skilled woodworker has difficulty accurately producing 3D contours.

The result is a piece that requires extensive finishing by hand.

A CNC machine allows every detail of the work piece can be defined perfectly in the CAD/CAM software and gives the operator time for to do anothe job while the machine produces the part.

The accuracy of the CNC machine is far beyond what can be achieved by hand, said Micromech.

Also, each CNC machined piece will need little hand finishing.

While programming is a labour-intensive process similar to cutting out the first piece by hand, once it is completed other pieces can be produced without constant attention.

All that is required is a person loading raw wood and unloading finished pieces on the machine and occasionally checking to be sure the tool hasn't worn out or broken.

The result is that architectural ornamentation can be produced at a much more competitive price on CNC machines, said Micromech.

* Routing and drilling - the Isel machine chosen is designed for production routing and drilling on a wide variety of materials including wood, plastics, MDF, solid surfacing materials and non-ferrous metals.

Very flexible and easy to use it is easily adaptable to nearly any woodworking problem.

For example, long pieces of moulding can be stacked side by side while the spindle traverses each piece to cut the pattern.

Another interesting piece introduced is called a corbel - a triangular decorative bracket that fits in the corner between a ceiling and wall.

The machine takes a solid block of wood and machines it down to an intricate 3D design on three sides.

These multi-sided pieces are mounted on a rotary table that moves the appropriate face towards the spindle one after another.

* High quality cuts - the Isel machine's shaft-and-bearing system produces very smooth, play-free motion and is an extremely rigid system that produces high-quality cuts.

It uses anti-backlash ball screws that have excellent power transmission due to the rolling ball contact between the nut and screws.

This type of contact ensures low friction, low wear and long life.

The ball screws also make it possible to produce wooden parts to the machine resolution of 0.013mm.

Micromech told manufacturingtalk.com that there are less expensive machines using rack and pinion gearing, which have too much play to make accurate cuts in small areas.

Also this type of gearing wears out quickly in the dusty environment of a carpentry shop.

The other main difference found between the Isel machine and the others was their use of servomotors to control cutting motion while other machines used stepper motors, which can give a 'stair-step' cutting effect.

With this set-up they can produce just about anything that customers require for example one asked for a moulding that looks like a grapevine with the grapes protruding in 3D.

From a picture of what was wanted, the image was scanned and then turned into a 3D model.

The artwork is coloured by the use of brushes and flood fill tools and each colour is assigned to an individual 3D-shape profile.

* Different profiles - the different types of profiles that can be generated include plane, round and angular.

The parameters of these profiles are controlled by defining the basic shape, start height, limit height and wall angle, giving almost total control over a wide range of 3D effects.

The program builds 3D reliefs by assigning a height to each pixel in the 2D image.

Then by providing their own artistic interpretation and designing the moulding in such a way that it can be machined quickly, a sample piece in MDF is given to the customer.

From the feedback the program is modified so that the finished pieces are exactly what they want.

Now other woodworking companies are switching to Isel 3D machine machines, said Micromech.

With the additional intelligence plugging devices into the various ports can provide commands in the programme to turn on a dust collector and an air blast to clean the tool or have a digital video camera pointing at the machine to monitor the machine.

* Micromech is the UK systems and distributor for Isel.

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