Three blind bores measuring Ø56.035 mm, Ø79.05 mm and Ø102.065 mm had to be machined in a pump housing made of EN-GJS-400-15 (GGG40). The short functional surfaces and limited available overtravel place high demands on tool guidance, stone arrangement and coordination between rough and finish honing.
DIAHON developed a dedicated FDS blind-bore honing tool with an HSK-A63 interface for each diameter. Separate roughing and finishing versions form a clearly defined two-stage process chain. The solution belongs to the coolEXact® honing technology for machining centres.
| Bore | Machining depth | Surface requirement | Available overtravel |
|---|---|---|---|
| Ø56.035 H6 | 11.5 mm | Rz 6.3 µm | 6.5 mm |
| Ø79.05 H6 | 19.8 mm | Rz 5.0 µm | 6.4 mm |
| Ø102.065 H6 | 29.0 mm | Ra 0.6 µm | 9.5 mm |
| Characteristic | Design |
|---|---|
| Component | pump housing |
| Material | EN-GJS-400-15 (GGG40) |
| Bore type | blind bores |
| Tolerance class | H6 |
| Machine interface | HSK-A63 |
| Process sequence | rough and finish honing with separate tools |
Rotational speeds, feed rates, pressures and other machine-specific settings are not published.
The approved tool drawings show FDS honing tools with honing stones distributed uniformly around the circumference. Designs with 16 honing stones were specified for Ø56.035 mm and Ø79.05 mm, while the Ø102.065 mm version uses 24 stones. The broad circumferential support improves guidance in the short blind bores.
All tools have an HSK-A63 interface and are designed for use on a machining centre. Separate tools for rough and finish honing allow size correction and surface generation to be adjusted independently. The applied coolEXact® technology combines a compact design with repeatable expansion and strong circumferential guidance.
Secure the pre-machining condition: The bore is supplied with a defined honing allowance. Position, diameter and initial geometry must be within the intended correction range before honing begins.
Rough honing: The first FDS tool performs size and geometry correction. The distributed honing stones support the tool around the circumference despite the short functional surface.
Limit overtravel: Only a small amount of run-out is available behind the functional surface. Tool length, stone position and stroke overlap are therefore matched to each diameter.
Finish honing: A separate finishing tool produces the final size and specified surface. This allows the second stage to be optimised specifically for size variation and roughness.
Verify the result: Diameter, top-to-bottom variation, roundness and surface finish are evaluated together. Quantitative results are available only for the Ø79.05 mm bore in the supplied records.
| Inspection criterion | Result | Assessment |
|---|---|---|
| Top-to-bottom diameter variation | 2 µm | low axial size variation |
| Roundness | 3 µm | uniform bore geometry |
| Surface finish | Rz 1.2 µm | drawing requirement of Rz 5.0 µm clearly met |
| Positions | acceptable | documented position check passed |
The measurements substantiate the two-stage process for Ø79.05 mm. For Ø56.035 mm and Ø102.065 mm, the sources document approved tooling concepts and drawing requirements but no comparable final measurements. The Ø79.05 mm results are therefore not attributed to the other two diameters.
Why separate rough and finish honing? The first stage performs most of the size and geometry correction. The second stage can then be tuned specifically for final size and surface finish.
Why are dedicated tools required for all three diameters? Diameter, machining depth and available overtravel differ. A dedicated design ensures that stone length, guidance and stroke overlap match each blind-bore geometry.
Which measurement results are available? For Ø79.05 mm, the records document 2 µm top-to-bottom variation, 3 µm roundness and Rz 1.2 µm. Only approved component and tool drawings are available for the other two diameters.
Which tool technology is used? FDS blind-bore honing tools from the coolEXact® tool system are used with an HSK-A63 interface and circumferentially distributed honing stones.
Separate FDS tools for rough and finish honing make it possible to machine the three H6 blind bores of a pump housing on a machining centre. The documented process proof for Ø79.05 mm achieved 2 µm axial size variation, 3 µm roundness and Rz 1.2 µm. Diameter-specific design of the stone arrangement and overtravel is the key to the short functional surfaces.
Related DIAHON section: coolEXact®.