I.The “Stabilizing Foundation” in a Constant Temperature Workshop
The three-coordinate measuring instrument is placed in a 26℃ constant-temperature workshop, with the temperature always maintained within a range that is comfortable for the human body. This can prevent the influence of environmental temperature fluctuations on the measurement. Its workbench is made of a thick piece of natural marble. Compared with common metal countertops, marble is minimally affected by temperature changes and is highly stable.
Before measurement, the staff will carefully calibrate this marble table to ensure that its inclination is within a controllable range. The cylinder head to be inspected is fixed on the table surface through three-point positioning pins to prevent temperature conduction or surface contamination caused by direct contact – this step can reduce the influence of external interference on the measurement results to less than 0.001mm.
II. Probe “Scanning” : Conducting a “full-body inspection” of the cylinder head
The measuring instrument is equipped with a mechanical arm fitted with a ruby probe, which is small and sensitive, and can inspect every part of the cylinder head in detail. It “dots” hundreds of key positions on the cylinder head according to the preset program, just like giving the cylinder head a comprehensive three-dimensional body scan.
There are three key areas for inspection:
Flatness: Select 50 sampling points at the joint surface between the cylinder head and the engine, and calculate the maximum height difference. The qualified standard is ≤0.05mm. If this value is exceeded, it may cause the airtightness of the engine to fail during operation.
Hole diameter accuracy: For 12 bolt installation holes, the probe takes 8 points along the circumference of the hole wall to measure the diameter deviation (allowable range ±0.015mm) and roundness (≤0.01mm). Out-of-tolerance will directly affect the stability of assembly.
Positional accuracy: Check the relative coordinates of the bolt hole group. The deviation of adjacent hole positions should be ≤0.03mm. This parameter determines the matching accuracy between the cylinder head and the engine block. A slight difference may lead to assembly jamming.
III. From “Manual Random Inspection” to “Data Closed Loop”
Traditional quality inspection relies on tools such as calipers and dial indicators. It takes 3 hours to inspect a single cylinder head and can only cover 20% of the key measurement points. The three-coordinate measuring machine compresses the detection time to 40 minutes and achieves 100% full-dimensional data collection.
It can also automatically generate detailed reports, recording the situation of each detection point, unlike handwritten records which may lead to errors. This report is like a “physical examination report” for the cylinder head. Customers can tell the quality of the product at a glance, which is more effective than any verbal guarantee.
The most remarkable feature of this instrument is that it can detect minute defects that are invisible to the human eye and ordinary tools. Some errors are as small as a human hair, but they can be a big problem for the cylinder head. And this is a piece of cake for a three-coordinate measuring machine, which can detect even the slightest error.
The three-coordinate measuring machine is like the “gatekeeper” of cylinder head quality, ensuring that every product leaving the factory meets the standards through precise inspection. Its existence makes “qualified” no longer a vague concept, but can be proved through real test data. This is also a manifestation of Heda Aluminum Industry’s insistence on product quality.