CAD vs CAM — The Basic Difference
- CAD (Computer-Aided Design) — Drawing the geometry (a DXF or DWG file)
- CAM (Computer-Aided Manufacturing) — Turning the geometry into a cutting path (G-code)
- CAD is generally done in AutoCAD, Rhino or SolidWorks
- CAM is done with the waterjet machine's own software (IGEMS, Contranest, Sigmanest)
- CAM sets the cutting order, the speed, the pressure, the garnet flow and the pierce point
- The CAM output is G-code (.nc, .ngc) → loaded into the machine control
Industry Standard CAM Software
| Software | Developer | Strength | Weakness |
|---|---|---|---|
| IGEMS | IGEMS R8 (Sweden) | Waterjet focused, 5-axis plus 3D nesting | Expensive licence |
| Contranest | Beckhoff integrated | Automatic nesting, the USEL Compact standard | Only with Beckhoff CNC |
| Sigmanest | Sigmanest LLC (USA) | Multi-machine management (large plants) | A complex learning curve |
| Almacam | Almacam (Spain) | Granite/marble focused | Little waterjet support |
| MetalixCAD/CAM | Metalix (Israel) | Sheet metal plus waterjet hybrid | Weak on stone processing |
IGEMS — The Sector Leader
IGEMS — the standard of the waterjet world, much as "Photoshop" is of its own. It integrates with most pump and machine manufacturers. IGEMS is a common choice on USEL waterjet machines.
- Full 2D, 3D and 5-axis support
- Automatic nesting — minimises slab waste
- Cut simulation — collision checking
- Quality levels Q1-Q5 — automatic speed calculation
- Pierce optimisation — finds the right point automatically
- Labelling plus reporting — for job tracking
- KMT, BFT, Resato, Flow and OMAX pumps are supported
Contranest — Beckhoff Integrated
Contranest — the standard software of the USEL Compact Waterjet model, working integrated with the Beckhoff CNC control. Its advantages:
- Tight integration with Beckhoff TwinCAT
- Nesting optimisation
- Preset standard cutting parameters
- A simplified interface for the operator
- Turkish language support (localised for the USEL Compact)
Nesting (Laying Parts Out Together)
Nesting — placing more than one part on a single slab with the least possible waste. Because the cost of a slab is high, a 5-10% difference in waste is economically critical:
- Manual nesting — the operator lays the parts out by hand; 15-20% waste is normal
- Automatic nesting — the software reaches 5-8% waste with an algorithm
- Two-way nesting — flipping plus rotating the parts
- Common-line cutting — cutting adjacent parts along a shared line (time falls by 10-15%)
- 5-axis nesting — transitions between lower layers with angled cutting
- Composite nesting — combining parts of different sizes
The Effect of Nesting
A good nesting algorithm brings a workshop's slab cost down by 10-15%. For a workshop using 1,000+ slabs a year that is a meaningful saving.
Cutting Path Optimisation
- Order — small detail first, then the large contour (for accuracy)
- Pierce points — gathered in corners that will not be seen
- Minimum idle travel — no needless movement
- Tilt angles (5-axis) — smooth transitions
- Common-line — adjacent parts on a single line
- Lead-in / lead-out — a smooth start and finish for the pierce and the exit
5-Axis Post-Processor
In 5-axis cutting the standard G-code from the CAM is not enough — a "post-processor" matched to the particular motion dynamics of the machine is required:
- RTCP (Rotation Tool Centre Point) — the tip position is held fixed while the axes rotate
- Lookahead — the machine calculates the position it is about to reach and adjusts the speed
- Tilt limit — staying within the A-axis limit
- Collision checking — the tool holder against the part
- Soft limit — preventing a breach of the physical boundary
- The post-processor is generally supplied by the machine manufacturer (USEL)
Software Training
- Official IGEMS training — one week, certified (abroad)
- The CAM module is included in the five-day USEL Academy programme
- Online video training (YouTube, the vendor portal)
- An in-workshop mentor system — learning from an experienced operator
- A software demo version — a 30-day trial before purchase