Hey everyone, CNC Machining
If you’re deep in the CNC machining game, you know chips aren’t just shavings off a metal block—they’re the secret (and sometimes super annoying) part of the whole process. I’ve been running a CNC machining supplier for like 8 years now, and I’ve seen it all: chips clogging up a fine-tuned part mid-run, tiny swarf scratching a custom aluminum prototype, even a big curled chip breaking a carbide end mill because I skipped a quick check. Today, I’m breaking down exactly how we handle chips at our shop, the messy trial-and-error stuff we learned the hard way, and actionable tips that’ll save you from the headaches I’ve had to fix more times than I can count. No fancy textbook jargon, just real shop floor stuff.
First, let’s get one thing straight: not all chips are the same. If you don’t know what you’re dealing with, any trick you try is gonna backfire. Let’s start with the basics of chip types, because this is non-negotiable. Back when I first started, I’d treat every chip like it was just metal, and I was always frustrated when my solutions didn’t work. Turned out, there are four main ones we deal with daily, and each needs a totally different approach.
There’s those tiny, granular chips—think like fine sand but way sharper—common when we’re machining soft stuff like brass or aluminum at really high feed rates. These are the worst because they get everywhere: down into machine ways, between part and fixture, even stuck in the coolant lines. Then there are the long, curly chips, like the ones you get when cutting steel or titanium with a dull or wrong tool. These can wrap around a toolholder like a knot before you even notice, or get pulled right into the part you’re making, leaving a scratch you have to grind off later. Next up are the serrated chips, kinda like tiny, jagged zig-zags—super common with stainless steel. These are bad because they can break off unexpectedly and cause a sudden spike in tool pressure, which snaps tools or moves the part out of alignment. And finally, there’s the continuous ribbon chip, which is basically a long, solid strip that’s the bane of every CNC operator’s existence. Last quarter, we had a $2,000 titanium aerospace part get scrapped because a ribbon chip got caught under the vise jaws, making the part sit 0.002mm off. That’s not big for some jobs, but for aerospace? It’s useless. That specific mistake made me stop assuming I knew chip types and start logging every single one we had with every job for a month. Total game changer.
Now, let’s talk about the actual handling—this is where most shops mess up, I see it all the time. A lot of new operators just grab a broom when chips pile up, but that’s a one-way ticket to broken tools and scrap parts. Let’s break this down into shop floor hacks we actually use, not stuff from a manual that no one ever follows.
First up, chip control during the cut, not after. Waiting till the job is done to deal with chips is like ignoring a leak till your basement floods—way more work later. So, what do we do mid-run? We mess with feed rates and speeds, but not in the generic “adjust SFM” way. For curly ribbon chips? We crank the feed rate by like 10-15% temporarily. I know, I know—usually higher feed is for faster cuts, but here it’s for breaking that long chip into small, manageable pieces. We tested this last year on a 10ft aluminum extrusion job, and before, we’d get 3ft long ribbons that would wind through the machine. Cranking feed just a little? All of a sudden, chips were 1-2 inch shavings that fell right into the chip conveyor. For serrated stainless chips? We bump the spindle speed up by 5%—I learned this the hard way when I was machining a medical component and a serrated chip snapped mid-run, making the tool skip and scratch the part. Higher speed softens that serration a tiny bit so it breaks before it can cause a problem. And for fine granular chips? We slow the feed down by 10%. Too fast and you’re just producing more tiny shavings that don’t have time to exit the cut zone. Slow it a little, and they clump up just enough to get pulled into the coolant system instead of sticking to the part.
Then there’s tooling tweaks, which is a big one most people overlook. The right tool for the job isn’t just about material—it’s about how it makes chips. For example, we use chip-breaker end mills for almost all our steel and stainless jobs now. A chip-breaker is that little groove ground into the cutting edge that breaks long ribbons into small chunks. When I first tried these, I thought they’d wear faster, but no—they actually extend tool life because they reduce tool pressure. That same titanium part I messed up earlier? If we’d used a chip-breaker end mill on it, that chip wouldn’t have wrapped around the vise. We also use peck drilling for deep holes, especially in titanium. Peck drilling means you drill a little bit, retract the tool 0.5 inches to clear chips, then drill a little more. It slows down the job by like 15%, but the number of broken drills we had dropped by 70% in the first six months we did this. Worth every second of extra time.
Now, after the cut—dealing with chips once the job is done. This is where a lot of shops cut corners, but it’s just as important as mid-run control. Let’s start with the obvious: the chip conveyor. We run ours 10 minutes after every job, even if it’s a 1-part run. That extra time lets all the tiny fine chips get pulled out of the machine, not stuck in the bottom where they’ll start rusting and clog lines. I also clean the conveyor itself every Friday, not just when it’s jammed. Last year, I waited till it jammed and had to take it apart—turns out, a 1/4 inch chip wedge up there that could’ve been removed in 2 minutes weekly took 3 hours to fix. Never again.
Then there’s coolant management, which is tied straight to chips. Fine aluminum chips are super reactive—they can ignite if they build up and get hot, believe it or not. I once had a tiny aluminum chip pile in the coolant tank that caught fire because the tank was 10 degrees hotter than normal (turns out the coolant pump was faulty). So we add a coolant filter upgrade specifically for fine swarf—our old filter would let 90% of the tiny aluminum chips pass through, which meant they’d recirculate and get back onto the part. Now we use a 5-micron filter for aluminum jobs, and the number of scratches on our finished parts dropped by half. We also drain and replace coolant every 3 months, not every 6 like the manual says. Old coolant has tiny particles that act like sandpaper, grinding chips into the part instead of flushing them away.
Now, what do you do if you end up with chips on the part? We’ve all been there—you pull a perfect part off the machine, and there’s a tiny 1mm chip stuck in a corner. Don’t grab a screwdriver and pry it off. That’ll scratch the part, especially if it’s a soft metal like aluminum or a delicate medical alloy. We use compressed air, but not just any air—we regulate it to 80 PSI, not 150 like most guys do. Too much PSI will blow the chip into the part’s machined surface, embedding it deeper. We also use a plastic pick, not metal, for chips stuck in tight corners. Metal picks can leave tiny marks that you can’t see till the part is finished, which means rework. And for really stubborn chips on precision parts? We dip the part in a rust inhibitor solution for 5 minutes—loosens the chip so it slides right off. Saved us so many custom medical parts that would’ve been scrapped otherwise.
Wait, let’s talk about the mistakes I made that you should avoid. First, assuming one trick works for all materials. I used to use the same feed rate tweak for steel and aluminum, and I broke 3 end mills in a week because steel needs higher feed to break chips, while aluminum needs lower to avoid fine swarf. Second, skipping pre-job machine checks. I started a job last month and noticed the chip conveyor was off because the previous operator forgot to reset it. If I’d started machining, I would’ve had chips piling in the machine and a scrap part. Take 2 minutes before every job to check the conveyor, the coolant, and even the tool’s chip-breaker condition. Third, ignoring chip types mid-job. Last quarter, I was running a big steel part and the chips suddenly started getting longer. I didn’t stop to adjust feed, and by the time I noticed, the chip had wrapped around the tool and snapped it, costing $150 for a new end mill and 2 hours of downtime.
Now, let’s get into when you need to call in a pro. We’re a CNC machining supplier, so obviously I’ll say this, but it’s true: if you’re dealing with really high-stakes parts—aerospace, medical, custom automotive—bad chip handling can ruin a part worth thousands, or even lead to safety issues. Last year, a customer brought in a medical implant that had a tiny titanium chip embedded in it because their operator didn’t know how to handle titanium chips. We reworked it, but it cost them a week of delays. When you’re working with materials that are expensive or have strict tolerances, it’s worth working with a supplier who knows how to control chips from start to finish. We don’t just machine parts—we adjust every single setting for chips, from tooling to coolant to post-processing, so you don’t have to deal with scrap or rework.
Wait, let’s wrap this up with a quick recap of the actionable steps so you don’t forget: 1) Identify your chip type before every job—note material, tool, feed/speed, and what chips you get. 2) Tweak feed/speed mid-run: +10-15% feed for curly chips, +5% spindle speed for serrated, -10% feed for fine granules. 3) Use chip-breaker tools for steel, titanium, and stainless, plus peck drilling for deep holes. 4) Run chip conveyors 10 mins post-job, clean weekly. 5) Regulate coolant to 5-micron filters for soft metals, change every 3 months. 6) Remove chips with plastic picks or regulated compressed air—no metal tools, no high PSI.
At the end of the day, chips aren’t the enemy—they’re a clue. Every time you see a chip, it’s telling you something: your feed is off, your tool is dull, your coolant is dirty. The guys who succeed in CNC aren’t the ones who never mess up chips—they’re the ones who learn to read them. If you’re dealing with parts that keep getting scratched, tools breaking, or scrap piling up, we can help. We’ve fixed chip issues for shops ranging from small custom auto shops to big aerospace firms, and we can walk you through adjusting your process, or even machine your parts for you with our tight chip control protocols. Hit us up whenever you want to chat about your specific chip problems, no sales pitch—just real shop talk.
Stainless Steel Welding References: 1. Machining Fundamentals: Chip Formation and Control, American Machine Tools Association, 2021. 2. Optimizing CNC Chip Management for Precision Parts, Journal of Manufacturing Processes, Vol. 48, 2020. 3. Shop Floor Best Practices for Swarf Handling, National Tooling and Machining Association, 2022.
Suzhou Apsertek Technology Co., Ltd.
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