Les Côtes 2, CH-2525 Le Landeron, Switzerland

In-process measurement solutions for CNC machine tools
Machine Tools Industry

Real-Time Feedback for
Closed-Loop Machining Control

In-process gauging on grinding machines and CNC lathes. Automatic tool compensation driven by live measurement data, not post-process correction after the part is already out of spec.

Subμm
Repeatability
Real-Time
Process Feedback
0%
Scrap Target
The Challenge

The Machine Doesn't Know What It Just Cut

Without in-process measurement, a CNC machine operates blind. It follows a programmed path, but it has no direct knowledge of the actual workpiece dimension being produced. Tool wear, thermal growth, material hardness variation, and coolant temperature all cause the real cut to drift from the programmed intent.

The traditional approach, machining a part, removing it, measuring it in the lab, then adjusting the machine, wastes time and material. Every part machined between corrections is a potential reject. On expensive materials or tight tolerances, this cycle of cut-measure-adjust is simply too slow.

In-process gauging closes the loop. The measurement happens during or immediately after the cut, while the part is still on the machine. The CNC uses this data to automatically compensate tool offsets in real time, eliminating drift before it produces scrap.

PRETEC ROBOTAST parallel guiding system for automated in-process measurement
PRETEC ROBOTAST — pneumatically actuated parallel guiding system for automated measurement

Our approach: We integrate measurement directly into your machining process. Air mandrels inside the grinding machine measure bore diameter during the spark-out phase. Electronic probes on ROBOTAST parallel guiding systems measure shafts and external features between operations. The measurement signal feeds your CNC controller for automatic offset correction, no operator intervention, no scrap.

Applications

Machine Tool Measurement Applications

From internal grinding to external turning, real-time measurement for the machining operations that demand the tightest dimensional control.

Internal Grinding - Bore Diameter

Air mandrels mounted inside the grinding machine measure bore diameter during spark-out. The CNC uses the live signal to determine when the target size is reached, then retracts the wheel, eliminating over-grinding and reducing cycle time.

Tech: Air Mandrels Mode: In-Process

External Grinding - Shaft Diameter

Electronic probes or air rings measure shaft journals during or immediately after cylindrical grinding. Feedback controls wheel dressing intervals and infeed compensation to maintain diameter across the entire batch.

Tech: Probes / Air Rings Mode: In/Post-Process

CNC Turning - Post-Process Check

ROBOTAST-mounted probes measure turned diameters between operations without removing the part from the chuck. Results trigger automatic offset correction in the CNC program. Ideal for unmanned or lights-out machining cells.

Tech: ROBOTAST Mode: Post-Process

Honing - Bore Size Control

Air gauging integrated with the honing machine controls stone expansion and stroke length. The gauge determines when the bore reaches target diameter and signals the machine to stop, preventing over-honing and ensuring bore geometry meets roundness specifications.

Tech: Air Gauging Mode: In-Process

Spindle Bores & Tool Holder Tapers

ISO and HSK taper inspection with dedicated air plugs and rings. Taper angle, diameter at gauge line, and runout must be perfect for rigid tool clamping and concentricity. We manufacture air gauges for standard ISO 30–50 and HSK A/E/F tapers.

Tech: Air Plugs/Rings Tol: IT4–IT5

Between-Operations Gauging

Standalone measuring stations positioned between machines on transfer lines. Parts are checked after each operation, turning, drilling, milling, with results feeding forward to the next machine for adaptive process control.

Tech: Air + Electronic Mode: Inter-Op
Closed-Loop Control

Three Stages of Machine Tool Integration

From pre-process setup to post-process verification — each stage serves a specific purpose in eliminating scrap and maintaining process capability.

01

Pre-Process Setup

Before machining begins, gauging verifies the incoming blank dimension, fixture position, and tool length. This eliminates setup errors, wrong blank, incorrect clamping, broken tool tip, before the first cut is made. Especially critical for unmanned production cells where operator intervention is not available.

Blank Verification Tool Check Setup Validation
02

In-Process Feedback

During the machining cycle, gauges measure the workpiece and feed real-time data to the CNC. The controller adjusts tool offsets automatically, compensating for thermal growth, tool wear, and material variation as they happen. This is the core of closed-loop machining: measure → compare → correct → continue.

Live Measurement Auto Offset Zero Scrap
03

Post-Process Verification

After machining, the finished part is measured on a dedicated bench or in-machine post-process gauge. This serves two purposes: confirming the part is within tolerance (quality gate), and providing offset data for the next part in the batch (feedforward correction). Results are logged for SPC and traceability.

Quality Gate Feedforward SPC Logging

Why PFL Group for Machine Tools

We build gauges that live inside and beside your machine — not on a bench in a separate room.

Direct CNC Interface

Our gauges output analog signals (±10V, 4-20mA) and digital protocols compatible with major CNC controllers — Siemens, Fanuc, Mitsubishi, Heidenhain. No middleware, no data conversion delays.

Shop Floor Proven

Air gauging thrives where other technologies struggle: coolant splash, oil mist, chips, and vibration. Non-contact measurement is inherently immune to contamination — the air jet cleans the surface before measuring it.

ROBOTAST for Automation

Our pneumatically actuated ROBOTAST system mounts directly on or near the machine. It extends to measure, retracts to clear — fully compatible with automated part loading and lights-out machining cycles.

Air + Electronic, One Supplier

Need air mandrels for bore measurement AND electronic probes for length and depth? We manufacture both — PRETEC probes and PFL air gauging elements — under the same roof with coordinated signal processing.

Integrate Gauging into Your Machine

Tell us what you're machining and how you want to measure it. Our engineers will design the right in-process or post-process solution.