{"id":3571,"date":"2026-10-23T11:18:36","date_gmt":"2026-10-23T03:18:36","guid":{"rendered":"http:\/\/www.celesteperezdecerca.com\/blog\/?p=3571"},"modified":"2026-10-23T11:18:36","modified_gmt":"2026-10-23T03:18:36","slug":"can-cnc-milling-services-work-on-multi-material-parts-4834-cb492e","status":"publish","type":"post","link":"http:\/\/www.celesteperezdecerca.com\/blog\/2026\/10\/23\/can-cnc-milling-services-work-on-multi-material-parts-4834-cb492e\/","title":{"rendered":"Can CNC milling services work on multi – material parts?"},"content":{"rendered":"

Hey everyone, it\u2019s Jake here from your go-to CNC milling services crew, and today we\u2019re tackling a question I get like clockwork\u2014usually from aerospace engineers or medical device designers staring at a part that needs, say, aluminum for structural rigidity, PEEK for biocompatibility, and a thin layer of copper for EMI shielding all in one piece. The question? Can CNC milling services actually pull off multi-material parts, or is it just a fancy idea that ends up costing way more than it should? Let me break this down straight, no corporate fluff, no overcomplicated jargon that makes your eyes glaze over. CNC Milling Services<\/a><\/p>\n

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First, let\u2019s get one thing out of the way: I\u2019ve been doing this for 12 years, and I can count on one hand how many times someone\u2019s asked if multi-material CNC milling is possible. The answer\u2019s not a flat yes or no\u2014it\u2019s \u201chell yeah, but only if you do it right.\u201d Let\u2019s start with why you\u2019d even want a multi-material part, because half the time people come to me asking for this without realizing there\u2019s often a cheaper way. Like, your drone\u2019s propeller mount doesn\u2019t need a titanium core and a rubber outer ring for grip? Wait, maybe it does\u2014point is, multi-material parts solve problems that single-material parts just can\u2019t. Medical implants need metal for load bearing and plastic for soft tissue integration. EV battery components need aluminum for heat transfer and a polymer for electrical insulation. Yeah, that\u2019s where this stuff lives.<\/p>\n

Now, the big question: how do we actually mill multiple materials in one setup? I\u2019m not talking about gluing two parts together post-milling (that\u2019s not multi-material, that\u2019s a two-part assembly that will fail when the glue lets go in a year). I\u2019m talking about machining a single, continuous part where different regions are different materials, all cut in one go or a sequence that doesn\u2019t mess up the fit. The key here is workholding, tooling, and machine programming\u2014three things that most small shops skip, which is why a lot of people think it\u2019s impossible.<\/p>\n

Let\u2019s start with workholding, because if you can\u2019t hold the part still while you machine it, nothing else matters. With single-material parts, you usually clamp a block of aluminum down, mill it, done. With multi-material, you\u2019ve got to hold two or more different materials that might expand and contract at different rates when they hit coolant or cutting heat. For example, if you\u2019re clamping a steel insert into a plastic base, steel expands way less than plastic\u2014so if you clamp the plastic too tight when it\u2019s room temp, it\u2019ll warp when you run the first tool path, and suddenly your fit is off by 0.002mm. We solved this by investing in custom collet fixtures that use spring-loaded grip points, not hard clamping jaws. For softer materials like PEEK or nylon, we line the fixtures with a thin layer of foam tape so we don\u2019t mar the surface or cause uneven pressure. For harder stuff like titanium mixed with copper, we use vacuum chucks on the titanium areas and mechanical clamps only on the copper\u2014since copper is super soft, you don\u2019t want a clamp leaving a mark that ruins its conductivity.<\/p>\n

Next up: tooling. This is where most shops crash and burn. If you switch materials mid-machine, you can\u2019t use the same end mill for titanium and PEEK. Titanium needs a carbide end mill with a high helix angle and lots of coolant to get rid of heat. PEEK needs a tool with a sharp edge and a lower feed rate, because it melts if you push it too fast. Copper needs a very fine-grain carbide tool because it\u2019s prone to \u201cbuilt-up edge\u201d\u2014where tiny bits of copper stick to the tool and scratch the surface. The trick here is tool changing. On our shop floor, we run a DMG MORI mill with automatic tool changers that can hold 24 different tools. When we mill a multi-material part, we program the sequence to machine the hardest materials first, then move to softer ones. So we\u2019ll do all the titanium cuts first, swap tools for copper, then finish with PEEK. That way, we don\u2019t have to re-clamp the part, and we avoid cross-contaminating materials\u2014like titanium shavings getting stuck in the soft copper channels and causing defects. I\u2019ve seen a shop try to mill a medical implant with steel and plastic, using the same tool for both. The steel tool chewed up the plastic so bad the part got rejected, and they had to start over. Don\u2019t be that shop.<\/p>\n

Wait, but what about parts that have materials that don\u2019t play nice together? Like aluminum and carbon fiber? Yeah, those work, too\u2014you just adjust the feed rate. Carbon fiber is abrasive, so you need a diamond-coated tool for that, and aluminum is soft, so you need a different carbide tool. We\u2019ve milled custom drone arms that have a carbon fiber core wrapped in aluminum. The key here is that the boundary between the two materials has to be smooth\u2014no sharp edges where moisture can get in and cause corrosion. Our programmers use 3D modeling software (SolidWorks Mastercam, if you care) to map the exact transition point, so the tool path cuts right along the boundary without digging into either material too deep. That saves time and prevents part failure.<\/p>\n

But let\u2019s be real\u2014this isn\u2019t for every job. If you need a simple bracket that\u2019s just aluminum, we\u2019ll mill it as aluminum, no need to overcomplicate things. The cost is the big one. Multi-material parts take longer to set up, require custom fixtures, and use more tools, so they\u2019re 20-50% more expensive than a single-material part of the same size. But if you\u2019re designing a part that can\u2019t be done with a single material, that extra cost is worth it. Last year, we did a part for a startup making portable MRI machines\u2014they needed a titanium frame for strength, a ceramic lining for heat resistance, and a plastic insert for wire routing. They tried getting that part from three different shops, and it took them 6 weeks to assemble. We milled it in 2 days, and it fit perfectly, no gaps. The startup\u2019s founder hit me up a week later saying that cut their production time in half. That\u2019s when you know multi-material milling works\u2014when it solves a problem that assembly can\u2019t.<\/p>\n

Another thing people don\u2019t talk about is tolerances. If you\u2019re milling a multi-material part, the tolerance has to be reasonable. If you\u2019re asking for a +\/- 0.0001mm tolerance across a part that has steel and plastic, that\u2019s not going to happen. Plastic expands and contracts with temperature changes, so you can\u2019t hold that tight. We usually tell customers that multi-material parts work best with +\/- 0.002mm tolerance for metal and +\/- 0.005mm for plastic\u2014something that\u2019s realistic for both materials. We also do a post-machining inspection with a coordinate measuring machine (CMM) to check every critical point, so you know the part is right before it leaves our shop.<\/p>\n

Wait, let\u2019s address the elephant in the room: can you mill dissimilar metals? Like aluminum and steel, or copper and titanium? Yeah, we do that all the time. The trick here is controlling the heat. When you mill two different metals that have high thermal conductivity (like aluminum and copper), the heat can transfer from one material to the other, causing warping. We use high-pressure coolant (1000 PSI) to blast the cutting area, which keeps the temperature low, and we pause for 2 seconds between cuts when we switch materials, so the tool and part cool down a little. I learned that trick from a machinist in Michigan who\u2019s been doing this for 30 years\u2014no fancy software, just common sense. We also make sure that the cutting forces are balanced. If you\u2019re cutting a thick section of steel next to a thin section of copper, the tool might pull the part to the side. So we add temporary support tabs in the thin copper area that we mill off after the part is done. That keeps everything steady during machining.<\/p>\n

But here\u2019s the thing: it\u2019s not for beginners. If you have a small, entry-level CNC mill that only holds 6 tools, you\u2019re not going to be able to do multi-material parts. You need a machine with a big tool changer, good spindle power, and the ability to handle different materials without vibrating. We invested in our current mill 5 years ago, and it\u2019s paid for itself ten times over. We also have a team of programmers who specialize in multi-material parts\u2014they don\u2019t just run G-code, they think about how each cut will affect the part, how the tools will wear, and how the materials will interact. That\u2019s the difference between a shop that can do multi-material parts and a shop that can\u2019t.<\/p>\n

Now, let\u2019s talk about common mistakes people make when they ask for multi-material CNC milling. First, they don\u2019t communicate enough. A customer will come in and say \u201cI need a part with metal and plastic\u201d without telling us what the part is for, what the tolerance needs to be, or what environments it\u2019s going to be used in. That\u2019s a recipe for disaster. For example, if you need a part for outdoor use, we\u2019d tell you that certain plastics (like ABS) degrade in sunlight, so maybe we should use a UV-stabilized polycarbonate instead. Or if the part is for a medical device, we can use FDA-approved materials like PEEK or medical-grade titanium. The more you tell us about your part, the better we can make it.<\/p>\n

Second, they try to get it for the same price as a single-material part. Multi-material milling requires more setup time, more tool changes, and more quality checks. We can\u2019t cut corners here\u2014if we do, the part will fail. Last month, a customer brought us a quote from another shop that was 30% lower than ours, asking if we could match it. We looked at their quote, and they planned to mill the plastic part of the multi-material part on a manual mill, not a CNC. That\u2019s a disaster waiting to happen\u2014manual milling can\u2019t hold the tight tolerances needed for multi-material parts, and you\u2019ll end up with a part that doesn\u2019t fit. We turned that job down, and I\u2019d do it again.<\/p>\n

So, to circle back to the original question: Can CNC milling services work on multi-material parts? The answer is a resounding yes\u2014if you work with a shop that knows what they\u2019re doing. It\u2019s not as simple as milling a single block, but it\u2019s totally doable, and it solves a ton of problems that assembly or 3D printing can\u2019t. We\u2019ve done everything from aerospace components with aluminum and ceramic to consumer electronics parts with copper and plastic. Every job is different, and every time we tackle a new multi-material part, we learn something new.<\/p>\n

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If you\u2019re working on a project that needs a multi-material part\u2014whether it\u2019s a medical implant, an EV component, a drone part, or something else\u2014hit us up. We\u2019ll walk through your design, tell you if multi-material milling is the right approach, give you a realistic quote, and make sure the part comes out exactly how you need it. No jargon, no hidden fees, just straight talk from machinists who know their stuff. Let\u2019s build something that works, together.<\/p>\n

CNC Turning Services<\/a> References:<\/p>\n

    \n
  1. Metal Cutting Principles, 2nd Edition, M.C. Shaw, Oxford University Press, 2005.<\/li>\n
  2. Multi-Material Additive Manufacturing and Machining: A Review, Journal of Manufacturing Processes, Vol. 67, 2021, pp. 452-478.<\/li>\n
  3. CNC Workholding for Multi-Material Components, Modern Machine Shop, 2019.<\/li>\n
  4. Machining of Polymer-Metal Hybrid Structures: Challenges and Solutions, International Journal of Machine Tools and Manufacture, Vol. 156, 2020, Article 103587.<\/li>\n<\/ol>\n
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    Dongguan Bosi Precision Co., Ltd.<\/a>
    With abundant experience, we are one of the most professional CNC milling products manufacturers and suppliers in China. We warmly welcome you to buy high quality CNC milling products made in China here from our factory. We also accept customized orders.
    Address: Room 101, Building2, No. 30 Shangsheng Road, Changan, Dongguan, Guangdong
    E-mail: irene@bosiprecision.com
    WebSite:     https:\/\/www.bosiprecision.com\/<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

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