GMMCO

• Material Used4140 Stainless Steel
• Tightest Tolerances+001″/-.005″

This featured grip plug is a critical aerospace part and is composed of 4140 stainless steel that was heat treated to 32-38 HRC. To manufacture the insert, a variety of CNC Swiss Turning processes were applied. Using a SR-32J Star Swiss type lathe with live tooling, we turned each side and turned the start of the lead thread to a chamfer of .06 x .45 degree with the M14 x 2.0 for the major diameter and pitch diameter, and with a thread relief having 2 radii of .060″. Next, using the machine’s y-axis capability with live tooling, we milled two .670″ wrench flats into the stem. Throughout the machining process we maintained tight tolerances of +.001″-.005″, with features on a common axis to be GD&T run-out of .010″ max. To conduct inspection we relied on an OGP touch probe and a vision system CMM, as well as micrometers, a custom thread gage, a drop gage, and a digital optical comparator. The final Grip Plug featured .875″ round bar stock, with a .786″ outside diameter and a thread relief diameter of .450″. We then labeled each carton with part and lot numbers, as well as the quantity. Packaging was limited to 50 parts per box, in accordance with aerospace bag and tag requirements. Included in each order was a raw material certification, complete with chemical and mechanical properties, and quality control verification. The project took 4 to 6 weeks to complete, and was then shipped to our PMA client for use in the aerospace industry.

• Tightest Tolerances+000″/-.005″ Concentricity of .004″ ±1°
• Material Used316 Stainless Steel per ASTM A479
• Max Material Finish63 RMS
• Estimated Part Weight½ pound

This featured insert orifice is used in natural gas extractions, and is composed of 316 stainless steel. To manufacture the insert, a variety of CNC machining processes were applied. Using a Haas CNC lathe with live tooling, we turned each side, with the second side requiring a 12″ precision radius on top of a 15 degree lead-in angle. Next, we milled 4 slots 90 degrees apart, with .125″ in depth through 2 78″-16 UN-2A threads. Throughout the machining process we maintained tight tolerances of +.000″-.005″, and a concentricity tolerance of .004″. To conduct inspection we relied on an OGP touch probe and a vision system CMM, as well as micrometers, pin gages, a custom thread gage, a drop gage, and an optical comparator. The final insert orifice featured 3.00″ round bar stock, with a 2.750″ outside diameter and a 2.020″ to 2.5625″ inside diameter. Each of 4 slots measured 2.188″ wide, and the total insert weighed 12 lb. We then labeled each carton with part and lot numbers, as well as the quantity. Packaging was limited to 60 parts per box, with each box weighing a maximum of 40 lbs. Included in each order was a raw material certification, complete with chemical and mechanical properties, and quality control verification. The project took 4 to 6 weeks to complete, and was then shipped to our client for use in the oil and gas industry.

• Capabilities Applied/ProcessesCNC Machining Inspection
• Overall Part Dimensions1.250″ Round Bar Stock O.D. 1.230″ I.D .417″

This featured fuel nozzle seal is used on a Pratt & Whitney JT8D jet engine – the power plant for thousands of MD-80 and DC-9 commercial aircraft in the sky today. Our engineering staff worked with Pratt & Whitney engineers to design the critical features of this part. To manufacture the seal, a variety of CNC machining processes were applied with custom made tooling. Using a twin spindle Traub lathe with live tooling, we turned each side, with both sides requiring a dual spring diaphragm, with a .0002″ to .0005″ knife edge radius on both the I.D. and O.D periphery. The knife edges were selectively nitride coated for hardness. Four slots at 90 degrees were CNC machined into the sealer support area below the knife edges. Twelve equally spaced .123″ to .127″ holes were drilled into the face. Throughout the machining process we maintained tight tolerances of +.0002″-004″, and a concentricity tolerance of .0005″. To conduct inspection we relied on an OGP touch probe and a vision system CMM, as well as micrometers, pin gages, a custom thread gage, a drop gage, and an optical comparator. Each seal is 100% inspected under a 20X power microscope for any visual imperfections and 100% vacuum tested for sealing.

• Part Length6 in
• Production Volume25 Units

At GMMCO, we pride ourselves on meeting our clients’ diverse machining needs. With our 5-axis Star CNC Swiss machine, we can accommodate stock from 0.050″ to 1.25″ in diameter, up to 6″ in length, and can handle up to 12 features on a single part. Our arrays of machining processes are appropriate for applications such as connectors, fasteners and fittings, and we feature a maximum production volume of 10, 000 units per run. And to ensure each project meets our high standards, we offer a full optical comparator, as well as CMM inspection capabilities. For more information about our CNC Swiss machining services, please contact GMMCO.