Computer-Controlled
Machining

01 / SAFETY & MACHINE

Start with a safe setup

Our group completed the mandatory safety training for the LY1285L machining centre with a Siemens SINUMERIK 828D controller at the University of Nottingham Ningbo China.

Safety points covered in training

• Personal protective equipment: safety glasses or goggles, laboratory coats and particle dust masks during preparation and operation. Long hair was tied back, and loose clothing and jewellery removed.
• Enclosure and emergency stop: the enclosure was kept closed and interlocked while the spindle was running. Emergency stops and door-interlock warnings were checked before machining.
• Chip and dust management: wood chips were vacuumed away only after the spindle had completely stopped and the cycle was paused or finished.

02 / CAM PREPARATION

From the model to a machining program

We used Siemens NX to define the stock and coordinate systems, assign cutting operations, simulate toolpaths and post-process programs for the SINUMERIK 828D.

Select a screenshot to inspect its full-resolution details.

2.1 · Import the part and define the stock

We imported Performance Test Part_69x50x14.5mm_step.prt, a test part measuring 69 × 50 × 14.5 mm. In the modelling module, a zero-offset bounding block defined the stock blank around the test body.

The machine coordinate system origin (X0, Y0, Z0) was placed at the top centre of the workpiece. A clearance plane 50 mm above the top face was defined for rapid traverse moves (G0).

2.2 · Define the tools and operations

We created a 2.5D/3D milling program with two operations under the mill_contour type.

Helical/ramp entry moves used a 5° ramp angle, avoiding a direct vertical plunge into the solid wood.

2.3 · Generate and simulate the toolpaths

We checked step-down levels, entry moves and containment boundaries for gouging and tool-shank collisions. A full 3D material-removal simulation let us inspect the in-process workpiece (IPW), including the corner dogbone reliefs and central pocket.

2.4 · Post-process and review the G-code

The new_post_Siemens_3_Axis post-processor generated ISO/Siemens .mpf programs for the LY1285L.

We reviewed the generated header and program blocks, including:

• CYCLE832(_camtolerance,1,1) — high-speed cycle call.
• S12000 M3 — spindle speed and direction, later updated for the speed tests.
• F1200 — feed rate in the reviewed output.
• SUPA G0 Z0.0 D0 — retract/tool-change block in the exported program.

03 / TOOLING & SETUP

Tooling, fixturing and alignment

Tool selection and setup

We prepared an Ø8 mm roughing end mill (R0.5 × 150 mm, as recorded in the tool notes) and an Ø4 mm finishing end mill (R0.5 × 20 mm). Each tool was mounted in an ER collet chuck, measured for stick-out, tightened with a collet wrench, loaded into the spindle or magazine and registered in the Siemens tool table.

Tool length calibration

The built-in contact tool setter was used to calibrate tool length inside the machining chamber.

Fixturing and work coordinate zeroing

The timber blank was mounted on the vacuum fixture table with high-strength double-sided tape backing. We aligned the workpiece axes and set the X/Y/Z work coordinate system (G54) using the Renishaw touch probe.

04 / CONTROLLER VERIFICATION

Check the program at the machine

Before cutting, we transferred the G-code by USB and checked it in the SINUMERIK 828D’s graphical simulation mode. We reviewed clearance planes, plunge-entry points, step-downs and boundary containment.

05 / TEST RESULTS

Eight cuts. A cleaner finish.

We machined eight identical profile blocks in reclaimed solid wood, varying spindle speed and feed rate to compare tear-out, vibration, finish and cutting time.

These are the group’s observations for this material, tooling and setup. The finishing pass is shown separately from spindle speed.