Our Products #4977932

This is an example of the inspection of small diameter valve guides. The diameter of each guide was 6 mm and the length of a guide was 30 mm. The valve guides were bored with a fine boring tool to remove the reaming marks from the previous machining process. All of the guides were bored with the same tool. The objective of the measurements was to determine the effect of tool wear on surface finish. Image (a) was a guide bored when the tool was new. Image (c) is the finish that was obtained after the tool machined a few hundred pieces. The worn tool used to produce the surface finish in image (c) is no longer able to remove the reaming marks. Image (b) shows a cylinder with a large number of pores of different sizes and shapes.

In addition to inspecting smooth diamond turned surfaces for surface flaws, IOMSprobes can inspect tapped threads for proper thread count, thread spacing, pitch and thread defects such as crossed threads and other flaws. An example of a scan of the entire surface of a threaded part is shown in the figure below.

In this example a bored combustion cylinder has been scanned using a displacement probe that can generate data which can be used to produce a two-dimensional image of the surface or a three dimensional profile image of the surface. The data is taken only once, but can be processed in different ways as desired. An image of the inside surface of the cylinder is shown in Figure 1. The diameter of the cylinder is about 80 mm.

Castings are designed to minimize the amount of metal removal in machining operations. However, if the cutting tool is not precisely aligned relative to the part being machined, a non cleanup condition could result. This is shown in Figure 1 in which a honing operation has failed to remove residual fine boring marks from the previous machining operation.

The red areas in the top and bottom of the image of Figure 1 indicate reversals of the axial velocity of the honing stones. The number of bright red areas indicates the number of honing stones in the tool. The cross hatch angle has been calculated from the data and is indicated at various locations on the image.

Fuel injectors inject gasoline or diesel fuel into a combustion cylinder. When the fuel-air mixture is compressed sufficiently, it either ignites spontaneously in a diesel engine or is ignited by a spark from a spark plug in a gasoline engine.

Gas direct injection, in which the air is first compressed and then fuel is injected into a cylinder, can improve engine efficiency and vehicle milesgallon, but the fuel must be injected at much higher pressure, usually tens of atmospheres. This means that the seal between the fuel injector surface and the input fuel line must be free of scratches or other defects that could enable fuel to seep out around the edges of the seal and cause a fire in the engine compartment.

Parts for gas direct injection are usually made of highly polished stainless steel. The part surfaces must be inspected to ensure that there are no scratches or other features that could cause gas leaks. One possible cause of scratches could be residual grit in the cylinder from the polishing operation. IOMS has inspected fuel injector cylinders to determine whether our inspection technology could detect such scratches. Results for an acceptable and defective fuel injector are shown below.

Brake calipers squeeze brake pads against brake rotor surfaces to stop a vehicle. The brake pads are pressed against the brake rotor by pistons that are moved by pressure from brake fluid injected into brake caliper cylinders. The cylinders have grooves machined into their surfaces to hold seals that contain the brake fluid. During manufacture the grooves can accumulate metal chips and shavings that prevent proper insertion of the seals. The inspection process determines whether the cylinder and grooves are clean and ready for assembly into a brake caliper unit.

Figure 1 is a photo of a brake caliper base that contains two brake caliper cylinders. Figure 2 is an approximate surface profile of the entrance to a brake caliper cylinder. Figure 3 shows a scan obtained with an IOMS 2D reflective probe of a clean cylinder groove. The cylinder could also have been scanned with a displacement probe that could display the surface profile. Chamfers appear in green. Figure 4 shows the same cylinder with a metal shaving in the groove.

The valve ports in these valve bodies range in diameter from about 5 mm to 25 mm and in length from about 20 to over 100 mm. The diameter of a valve port can change in discrete increments along its length and the valve ports are intersected by multiple slots that segment each valve port into short cylindrical segments or journals. The journal surfaces are diamond turned and are highly reflective. Defects in the valve ports can consist of pores, chatter, delamination, metal flakes and other machining defects.

Graphs of valve port surface finish display circumferential angles from 0 to 360 degrees along one axis, depth into the cylinder in mm along the second horizontal axis and relative detected laser intensity along the vertical axis. Examples of these graphs are shown below. Figure 2 shows a valve port with acceptable surface finish, Figure 3 shows a valve port with excessive porosity and Figure 4 shows a valve port with both chatter and porosity. The signal intensity value

IOMS probes can inspect the inside surfaces of cylindrically symmetric parts with diameters as small as 5 mm and as large as several hundred mm. An example of a part with a large inside diameter is shown in Figure 1. This is a section of a honed aluminum tube 10 inches (254 mm) in diameter. The probe scans the surface with a focused beam of laser light and the detector in the probe detects the reflected light signal. The data is collected and stored in computer memory from which it can be displayed and processed. A photo of the experimental setup is shown in Figure 1.

Another technique for finishing combustion cylinders is to spray the bored surface with liquid metal to eliminate the formation of pores when the surfaces are honed. This technique has its own problems, however, since the spray nozzle that deposits the liquid metal could leave solidified drops of metal on the surface of the cylinder or cause cratering of the surface if drops of metal splatter on the surface during spraying.

Figure 1 shows an image of a surface that has been coated by a rotating nozzle. Figure 2 is a scan of a cylinder showing solidified droplets and surface craters caused by the bombardment of small drops of metal. Dark spots on the image of Figure 2 are solidified drops of metal that protrude above the surface. Light colored regions are craters produced by metal droplets bombarding the surface.