When I first started out as a rubber roller supplier fifteen years ago, I made a mistake that cost a client half a production run of printed packaging materials. Their flexo press kept skewing labels, and they traced the issue back to a rubber roller that wasn’t aligned properly. The problem, I later learned, was that the concentricity of the roller—how evenly it spins around its central axis—was off by just a fraction of a millimeter. For anyone working with rubber rollers, that tiny gap is where big losses start. These days, every roller we ship leaves our facility with a documented concentricity check, and I want to walk you through exactly how we do it, why it matters, and how you can check it yourself too, whether you’re on a shop floor or troubleshooting a machine at three a.m. when production is down. Rubber Roller
First, let’s get clear on what concentricity actually is, because it’s not just a buzzword thrown around by quality control teams. A perfectly concentric rubber roller spins around its center point, so every point along its outer rubber surface is exactly the same distance from that center, even when it’s moving at high speed. If it’s not concentric, different parts of the roller will stick out slightly as it turns. That causes all sorts of headaches depending on what the roller is used for: in printing, it leads to uneven ink laydown, streaks, or misaligned text; in textile processing, it can create uneven tension in fabric, leading to wrinkles or breaks mid-run; in converting, it causes misfeeds or torn material. For our clients—whether they run small local print shops or large national packaging facilities—even a 0.05mm deviation can shut down a press. That’s why checking concentricity isn’t just a quality step; it’s a production lifeline.
When we teach our team to check concentricity, we start with the basics: making sure the roller is set up properly, because a wobbly stand or a bent machine arbor can skew results. First, you need a stable, level setup. We use a pair of V-blocks for this—you can get them for a few hundred dollars, but even a well-made set of wooden V-supports works in a pinch. Place the roller’s metal core (not the rubber surface) in the V-blocks, and make sure it can spin freely without rocking. If you set it on a flat table and it tilts to one side, that’s a sign the core is bent, or the blocks aren’t level—fix that first, because a bad setup will give you bad numbers.
Next, you need a measuring tool. There are two main tools we rely on, depending on whether we’re checking a new roller during production or troubleshooting an existing one: a dial indicator (also called a dial gauge) and a straightedge with feeler gauges. For precision work on new rollers, the dial indicator is non-negotiable. It has a small, pointed tip that you press against the surface of the roller, and it measures tiny variations in distance. You can clamp the dial indicator to a rigid stand, so the tip is touching the outer rubber surface, just light enough that the gauge moves when you spin the roller.
Wait—important note here: when you set up the dial indicator, don’t just stick it anywhere. For a full check, you need to measure at multiple points along the roller, because concentricity issues can be localized to one section, not the whole thing. A common mistake people make is checking only the center of the roller, but if the end is off, that will still cause problems when you feed a full width of material. We typically take measurements at three points: 25mm from the left end of the rubber, the exact center of the roller, and 25mm from the right end. For wide rollers (anything over 1 meter long), we add a fourth point midway between the center and each end, so we have five total measurements.
Once the indicator is in place and set to zero (that’s your starting point, so when you spin the roller, you can track how much the distance changes), slowly turn the roller by hand. Watch the dial—if the needle moves more than the tolerance for your application, you have a concentricity issue. What tolerance is acceptable? That depends entirely on what you use the roller for. For high-resolution flexo printing, we require maximum 0.02mm deviation. For laminating rollers, a 0.05mm deviation is usually okay, because the material is thicker and less sensitive to tiny shifts. For our clients, we always share a recommended tolerance chart based on their machine type so there’s no confusion.
If you don’t have a dial indicator—maybe you’re in a remote shop or troubleshooting on a weekend—you can use a straightedge and feeler gauges, and it still works, just with a little more room for human error. Grab a steel straightedge that’s at least as long as the roller’s rubber surface. Lay it across the top of the roller, touching the rubber at both ends and the center. Then, take a set of feeler gauges (those thin, graduated metal strips) and slide them between the straightedge and the roller at the highest point of the gap. The thickest strip that fits in the gap is your approximate deviation. This method is less precise than a dial indicator, it’s only accurate to about 0.1mm, but it’s great for quick checks when production is down and you don’t have a precision tool handy.
Now, a common question we get from clients: is concentricity the same as roundness? Short answer: no. Roundness checks if the roller’s surface is a perfect circle, while concentricity checks if that circle is aligned with the roller’s core. A roller can be perfectly round, but if its core is off-center, it’ll have bad concentricity. Or the core could be perfect, but the rubber could be unevenly applied, making the surface not round—both issues cause problems, but they’re different. When we manufacture a rubber roller, we first machine the metal core to exact dimensions, then vulcanize the rubber to the core, then grind the rubber surface to the correct roundness and concentricity. Our CNC grinding machines hold tolerances down to 0.01mm, which is why our clients trust us for high-speed runs.
We also have a protocol for checking concentricity on installed rollers, because you don’t always have to remove a roller to test it. If a roller is already in the machine, you can use the same dial indicator method, but you’ll clamp the indicator to the machine’s frame instead of a separate stand. Make sure the indicator’s tip is touching the rubber surface, away from any grooves or patterns, and spin the roller by its drive gear (don’t turn it by hand, because your hand can introduce small wobbles). If the machine has a motor, you can run it at low speed to check, but never go faster than a quarter of your normal operating speed, because running a roller with bad concentricity at full speed can damage the rubber or the machine itself.
Wait, there’s a trick we use when checking installed rollers: mark the top of the roller with a piece of tape before you start. That way, if the dial’s needle doesn’t return exactly to zero after one full spin, you know the issue isn’t just concentricity—it could be a bent core or a worn bearing in the machine. That small tape mark saves us so many troubleshooting calls from clients who think their new roller is bad, when actually it’s a worn part in their press.
What do you do if you find a concentricity issue on a new roller? That’s why we have our QC process: every roller gets three checks during manufacturing, so almost never does a bad one leave our shop. But mistakes happen—human error in grinding, or a core that got nicked during shipping. If you find an issue on a roller you bought from us, our team will handle it same-business-day, no hoops to jump through. For used rollers, if you notice streaks or uneven tension, checking concentricity is the first step. Sometimes you can re-grind the rubber to fix a small deviation, but if the core is bent, you might have to replace the roller entirely.
Let me share a recent story that drives this home. A client in Ohio called us last month, panicking because their 8-color flexo press was running 20,000 label rolls a week, and every third roll had a faint white streak across the middle. They checked all the anilox rollers, the doctor blades, even the ink, and nothing worked. We walked them through a quick concentricity check on the print rollers, and they found that the central print roller had a 0.08mm deviation—just a hair over their acceptable limit. They ordered a replacement from us, installed it that night, and didn’t have a single streak the next day. That’s the difference between knowing how to check this and not.
A few final tips to make your checks accurate: first, always check in multiple positions along the roller. We once had a client who only checked the end of a roller, and the center had a 0.1mm deviation that went unnoticed for months, causing slow, hidden wear on their machine’s bearings. Second, don’t check a roller right after it’s been sitting in a cold environment—rubber expands and contracts with temperature, so let it acclimate to your shop’s temperature for at least two hours before checking. We keep all finished rollers in our climate-controlled QC room for 24 hours before testing, that small step eliminates temperature-related errors. Third, when using a dial indicator, make sure you don’t press the tip too hard into the rubber—you’ll distort the soft surface and get a false reading. Light, consistent pressure is key.
At the end of the day, concentricity isn’t just a technical spec—it’s about keeping your production running smoothly, avoiding costly downtime, and getting consistent, quality output for your customers. As a rubber roller supplier, our job isn’t just to sell you a roller; it’s to make sure it works for your specific machine and application, and that starts with those concentricity checks we do in our shop, and the guidance we give our clients to do the same.
If you’re struggling with uneven output, worn machine parts, or just want to make sure your rollers are performing at their best, reach out to our team. We don’t just provide rubber rollers—we provide technical support, quick turnarounds, and a quality guarantee that every roller leaves our facility meeting exact concentricity standards for your use case. Don’t let a tiny misalignment derail your production runs.
Silicone Products References
- American Society of Mechanical Engineers. (2017). Measurement and Quality Control for Rotating Machine Components. ASME B89.3.10-2017.
- Rubber Division, American Chemical Society. (2020). Vulcanized Rubber Roller Manufacturing and Performance Specifications. ACS Rubber Division Technical Report Series.
- Flexographic Technical Association. (2019). Guide to Roller Alignment and Concentricity Checks for Flexographic Presses. FTA Technical Bulletin 104-19.
Shenzhen Anfeng Rubber Plastics & Hardware Products Co., Ltd.
As one of the most professional rubber roller manufacturers and suppliers in China, we also support customized service. Please feel free to buy rubber roller made in China here and get pricelist from our factory. Quality products and reasonable price are available.
Address: 2nd Floor, Building 3, Guancheng Science Park, No. 22, Bihu Road, Tangli Village, Fenggang Town, Dongguan City, Guangdong Province, China
E-mail: anfengrubber@yeah.net
WebSite: https://www.af-rubber.com/
