Known limitations
OpenChuckCAM is in early development. Read this page before you rely on it for a real job. It describes the development version; each release’s copy of this guide describes that release, and its release notes list what changed.
You check every program
The program does not know your machine, your fixture or your tool. Before you run a program:
- check the origin, the height of the rotary axis, the tool lengths, the direction of A and the unwinding at the end of the program on your controller;
- run an air cut first, with no tool and no material.
Checking G-code before you run it says how. The Makera Z1 air cut and safe-practice checklist are the project’s own starting points.
Very little has run on a real machine
The project owner has run attended air cuts of two reference programs on one Makera Z1, and one small first cut in tooling board. Nothing else has been run, and nothing has been run on any other machine.
Some values in the built-in Makera Z1 profile have not been confirmed on a machine. The program marks them as unconfirmed, for example “5 machine values unconfirmed” in the status bar, and you must measure them on your own machine. See Confirm machine profile values.
What the program covers
- Machines
- 4-axis rotary work only: the work is held in a chuck and turned by one rotary axis, called A, which turns about X. There is no 3-axis flat-bed milling, no 5-axis work and no second rotary axis.
- Controllers
- Two posts: the Makera Z1, and LinuxCNC (the one the project uses to check its output). Other controllers need a post you write and check yourself. The output is in millimetres only, and A is continuous: it does not wrap at 0 to 360 degrees.
- Collisions
- The program does not model the chuck, a tailstock, the spindle, the tool holder or the machine body, and does not check them against the part. The chuck is represented only by a held region, a length at the end of the stock that is never cut. The flute length and shank of a tool are not checked against the depth of a roughing layer. Check clearances yourself.
- Models
- STL (ASCII and binary) and STEP. An STL file has no exact surface, so accuracy is measured against its triangles. A STEP file keeps its exact faces and edges for selection, drilling and swarf, but most toolpaths on a STEP part are still computed from a mesh made from it. STEP files from CAD programs other than OpenCASCADE have had little testing. A changed model cannot be re-imported into a project, and drawings (DXF or SVG curves) cannot be imported.
- Strategies
- Rotary roughing; facing; helical, axial, indexed and simultaneous 4-axis finishing; rest machining; pencil clean-up; edge and curve following; swarf; radial drilling. Swarf and radial drilling need a STEP model. Reaching tight inside corners is limited. Simultaneous 4-axis finishing can refuse a part it cannot follow; it says so instead of cutting it badly. There are no canned drilling cycles in the output.
- Project files
- The project format may still change before the first release.
Time and size
Generating toolpaths and simulating are not instant. On the tutorial’s small part, generating two operations and simulating the cut each took about a minute on a computer with no graphics card. Fine stepovers on large parts take much longer, and the simulation’s cell size trades accuracy against memory and time. The programmed time the program shows is the sum of the moves at their programmed feeds, not an estimate of the machine’s time.
Systems
Development builds exist for Linux, Windows and macOS (Apple silicon). They are not signed. Most hands-on checking has been done on Linux; the Windows and macOS builds have had less.