Wayne Wentworth
ADVANCED MANUFACTURING NOW MODERN MANUFACTURING PROCESSES, SOLUTIONS & STRATEGIES
Advances in Ti Machining—Do More on Less Floor a T
he demand for titanium components by the aerospace industry began as a whisper about 15 years ago and steadily grew to a sustained, raucous shout over the
last fi ve and likely won’t quiet for several more. Since Mitsui Seiki participated in an OEM’s research more than a decade ago to develop the machine tool technology to optimally cut this very hard and relatively diffi cult material, the knowledge base in the industry has evolved to the point at which we are all up to speed about the machine tool requirements—the ability to do low-frequency machining without chatter, a suit- able design and robust structure of optimal height-to-width ratios on columns and tables to handle the high bending moments, ideal ballscrew locations for axis stability and hand scraping over all to provide the accuracy needed to make quality parts from this challenging material. We’ve also learned a lot about the best cutting tools, feeds and speeds, through-coolant spindles, motors, tool taper interface sizes and styles, and coolant fl uids and systems for Ti applications. Where industry is now, at least in aerospace where I spend a lot of my time, is the phase of refi ning the Ti machin- ing process—continuously improving it, squeezing the cycle time out of it, and of course doing it all more effi ciently with no impact on fl oor space. In essence they want to produce more on less fl oor. Here are the areas that have made the greatest contributions recently in Ti machining: Cutting tools—Most leading cutting tool manufacturers have been putting and continue to put signifi cant resources in R&D for new solid carbide end mills and indexable inserts for cutting Ti. Like the trend in general, they have their “go-to” proven grades, and they are now tweaking the styles with a special radius, a special grind, a special coating. As an example, new 1" (25.4-mm) diameter seven-fl ute high feed end mills with a spe- cial grind are being used now on engine mount parts at an OEM facility that are allowing us to run at 357 sfm (109 m/min) at 1363 rpm and a feed rate of 80 ipm (2032 mm/min) , with a 0.9" (22.9 mm) axial depth and a 0.1" (2.54-mm) radial depth. It’s not taking that deep of a cut, but it moves through the material fast. A conventional end mill would fall apart in these conditions.
12
AdvancedManufacturing.org | February 2017
Cutting and toolpath strategies—One way to achieve bet- ter cycle times is by carefully analyzing cutting strategies and CAM toolpaths. I’ve seen notable improvements using tro- choidal milling, essentially a peel milling approach that uses a series of circular cutting paths at the full depth of cut. Coolant and coolant handling—Moving chips out of the cutting zone is critical in Ti applications. New biostable blends are coming on the scene that are particularly friendly to these high-pressure coolant cutting conditions with en- hanced lubricity technology that can extend tool life, improve fi nishes, are corrosion resistant and are economical to use.
Often, central fi ltration systems can be placed out of the production area entirely. Some fi gures cite a 25% fl oor space savings.
Relevant to coolant, I’m seeing more centralized systems be- ing installed out in the fi eld, even among smaller companies serving their FMS, cells, or a certain department. In addition to the benefi ts of having fewer and more effi cient pumps, less power usage, longer coolant life and easier recycling, this is one of the ways to save space on the shop fl oor. Cool- ant tanks near a machine can sometimes double the space requirement of the machine tool alone, plus you need space for maintenance access. Often, central fi ltration systems can be placed out of the production area entirely. Some fi gures cite a 25% fl oor space savings, which of course means you can increase production by 25% by that strategy alone. Machine tool versatility—Machine tools with multi-func- tionality is a trend we have been seeing and reading about for many years. However an added functionality to note with regard to Ti machining is deburring within the machining center’s work envelope using brushes with ceramic particles in them. Deburring is one of those operations that is most always done outside of the machine by a person sitting at a bench. Now it can be a programmable process.
Key Account Applications Engineer Mitsui Seiki USA Inc.
www.mitsuiseiki.com
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88 |
Page 89 |
Page 90 |
Page 91 |
Page 92 |
Page 93 |
Page 94 |
Page 95 |
Page 96 |
Page 97 |
Page 98 |
Page 99 |
Page 100
