How to work with us

Splines or vectors that have numerous nodes are problematic. This is most noticeable in curved vectors, a spline or faceted curve will have several nodes which are not a true curve.  Splines result in extra time to correct the CAD or mean that cuts are not as smooth as they could be.  Polylines constructed with arcs will typically have 3 nodes for each arc; the start , end and midpoint.  When these are translated into machine code, rather than generating several ‘go to’ commands it instructs the machine with a line of code with the radius and an endpoint and results in smooth movements and cut edges.

Rather than sending one file per part, please send through all parts that will be cut from the same material in one file.  ie, if 6 parts are to be cut in 5mm clear cast acrylic, and 4 parts are to be cut in 18mm MDF, please send 2 files.  The parts can be nested on the material, but we can also nest parts efficiently when we receive them to maximise material utilisation.

Gap between parts

Certain materials are usually best cut conventionally (anticlockwise), and others are best climb cut (clockwise) when CNC routing. Because of this, parts should not share perimeter vectors, and they should have gaps between them. We can advise on the appropriate gap between parts, as this will be dependent on the material, cutter size and part geometry. For Example, in 18mm stock for medium to large body components we recommend gaps of 11mm.

Gap around material perimeter

Sheet materials are often supplied with rough cut edges, and are rarely square. Because of this it is advisable to leave a gap of 10mm around the perimeter of the material. For example, we recommend a maximum component size of 1200x2420mm being cut from 1220x2440mm sheet size.

Tolerances for mating parts

Where a particular fit between parts is required, please get in touch. Material thicknesses can vary by large margins which can impact component assemblies.  For example, 18mm birch plywood can be 17.5-18.8mm  from batch to batch.  We can advise on current stock thickness so mating geometry can be adjusted accordingly. Typically there is a 0-0.25mm offset between male and female mating geometry depending on the joint design and fit required.

Tabs

Holding parts down for CNC routing is performed by vacuum. Small parts can deflect during cutting as they don’t have the surface area to be fully fixed by vacuum. To assist the fixture, we can use small tabs which attach the cut part to the material negative. Typically these tabs can be 2x5mm, and can be removed using a sharp scalpel. We can advise on whether tabs are necessary when reviewing your file, and we can also quote to remove the tabs after machining.

·       Ensure your design is scaled correctly and uses the appropriate units (mm or inches) based on the CNC machine's settings.

·       Ensure enough clearance between features (e.g., holes, edges, etc.) to prevent tool collisions.

·       Before submitting files, double-check for geometry errors like intersecting vectors or missing connections.

If you need help with a specific part of preparing files for CNC? We are happy to assist. Get in touch today.