{"id":3582,"date":"2026-10-10T15:26:36","date_gmt":"2026-10-10T07:26:36","guid":{"rendered":"http:\/\/www.marcelatroncosoc.com\/blog\/?p=3582"},"modified":"2026-10-10T15:26:36","modified_gmt":"2026-10-10T07:26:36","slug":"how-to-adjust-the-filling-volume-for-solid-products-in-a-vffs-machine-4294-c957d9","status":"publish","type":"post","link":"http:\/\/www.marcelatroncosoc.com\/blog\/2026\/10\/10\/how-to-adjust-the-filling-volume-for-solid-products-in-a-vffs-machine-4294-c957d9\/","title":{"rendered":"How to adjust the filling volume for solid products in a VFFS machine?"},"content":{"rendered":"

If you\u2019ve ever stood in a food packaging plant, a pharmaceutical production line, or even a snack manufacturing facility, chances are you\u2019ve seen a Vertical Form Fill Seal (VFFS) machine humming along, turning a flat roll of flexible film into perfectly sealed, bagged products at high speed. As a VFFS supplier, I get asked this question almost every day: \u201cHow do we adjust the filling volume for solid products on this machine without wasting material, slowing down production, or compromising seal integrity?\u201d It\u2019s not a trivial query\u2014for solid goods like granola, plastic pellets, pharmaceutical tablets, or frozen vegetables, getting the filling volume right means the difference between customer complaints, lost revenue, and even regulatory headaches for strictly controlled industries. Vertical Form Fill Seal Machine\uff08VFFS\uff09<\/a><\/p>\n

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First, let\u2019s ground this in what makes solid product filling different from liquid. Liquids flow predictably, so their volume adjustment often relies on timed flow or pump calibration. Solids? They\u2019re inconsistent. Granules can bridge, pellets bounce, and flaky products shift mid-fill. A volume change for solids isn\u2019t just turning a dial\u2014it\u2019s a system of checks, small tweaks, and paying attention to variables that don\u2019t show up on a liquid filling line. Over my 12 years as a VFFS provider, I\u2019ve walked more than 70 production lines through this process, and the most common mistake I see is trying to adjust the machine too quickly, without stopping to audit the product itself first.<\/p>\n

The starting line for any volume adjustment, in my experience, is not the machine settings\u2014it\u2019s the product. You can\u2019t adjust filling volume intelligently if you don\u2019t know how your solid product behaves. For example, if a client is switching from filling 100g of raisins per bag to 150g, the first thing I ask is: \u201cWhat\u2019s your bulk density, and does that density change with how you handle it?\u201d Raisins have a bulk density of about 0.6 g\/cm\u00b3, but if you\u2019re loading them from a hopper at high speed, they can compact, making a volume-based fill feel like a weight overfill. That\u2019s a critical point: most VFFS solid filling systems are either volume-based (using a measuring cup, auger, or volumetric chamber) or weight-based (though weight-based is more common for higher precision, and often paired with volume adjustments as a check). Wait\u2014no, correction: for many mid-range VFFS lines, especially for snack foods and light solids, volumetric filling is standard, but weight verification is non-negotiable.<\/p>\n

Let\u2019s break this down step by step, as I\u2019d walk a line operator or maintenance team through it during an on-site training, or over a virtual call when they\u2019re trying to tweak settings at 2 a.m. during a production run.<\/p>\n

Step 1: Define Your Adjustment Trigger, and Separate \u201cDesired Change\u201d From \u201cActual Volume\u201d
\nFirst, stop and ask: Are you adjusting because your product specs changed, or because the fill is off target now? A lot of times, operators see a 5g gap on the checkweigher and jump to turn the volumetric dial, only to find out the hopper is clogged or the film is stretching differently than last shift. For example, last year I worked with a small granola bar manufacturer that tried to bump their fill from 80g to 90g mid-run, only to have a batch of bags underfilled by 12g. The issue wasn\u2019t the volume setting\u2014it was that their granola had a higher oat flake content that day, which was more aerated, so the volumetric cup was holding less per volume than the denser mix they\u2019d run the week before. So rule number one: before touching any machine controls, confirm the change is not product-related. Pull a sample of the current run, weigh 10 representative units, measure the bulk density, and note if there\u2019s any variation in particle size. That takes 10 minutes, and it avoids hours of wasted product.<\/p>\n

Step 2: Match Filling Mechanism to the Adjustment Need
\nVFFS lines use different filling mechanisms for solids, and how you adjust volume depends entirely on which one you\u2019re running. I can\u2019t stress this enough\u2014adjusting an auger filler is nothing like adjusting a cup filler, and messing up one for the other will lead to inconsistent fills.<\/p>\n

Let\u2019s cover the three most common solid filling setups my team supplies:<\/p>\n

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  1. Volumetric Cup Filler: This is the workhorse for snacks, frozen foods, and non-medical solids. It uses a rotating or oscillating cup that\u2019s filled with product, then dumped into the formed bag. Volume here is tied directly to the size of the cup, but many lines have adjustable cup inserts or variable depth to change fill volume without switching the whole cup. For example, if you have a 100ml cup, adding a 10ml insert will drop the fill volume to 90ml, or removing dividers inside the cup can increase volume for bulkier solids like popcorn. When adjusting a cup filler, the key is to make small changes\u2014start with a 5% change in cup volume, not 20%\u2014because the cup\u2019s ability to hold consistent product relies on how the product settles in it. A common trick here is to tap the side of the cup after filling, to release any trapped air; for aerated products like puffed rice, that tapping step can change volume by 10% on its own, so don\u2019t skip it before calibration.<\/li>\n
  2. Auger Filler: This is used for fine, dense solids like pharmaceutical powders, coffee grounds, or spices. Instead of a cup, an auger spins to move product from the hopper into the bag, with volume based on how many turns the auger makes and the pitch of the flighting. Adjusting volume here means changing either the number of auger turns per fill cycle or swapping to an auger with a different flight pitch. But critical note: auger fill accuracy drops if the product\u2019s density changes, so if you\u2019re adjusting volume by more than 15%, you should also run a weight check immediately after. Last quarter, a specialty spice company I work with tried to increase their turmeric powder fill by 20% via auger turns, and ended up with bags that were overfilled by 18g because the powder compacted in the auger housing as it spun faster. We fixed it by switching to a higher-pitch auger, so the product moved more smoothly, and only increased turns by 5% to hit the desired volume.<\/li>\n
  3. Gravity Filler (for free-flowing large solids): Think frozen veggies, plastic parts, or hardware. These products flow easily, so volume is adjusted by changing the gate opening at the bottom of the hopper, or the drop time. The big gotcha here is that large solids don\u2019t stack the same way as fine powders\u2014if you widen the gate too much, you\u2019ll get uneven distribution, with more peas at the top of the bag and corn at the bottom. For these, I recommend adjusting gate size in 1mm increments, not percentage points, because particle size plays a bigger role than volume percentage.<\/li>\n<\/ol>\n

    Step 3: Calibrate With Weight, Not Just Volume Readings
    \nEvery VFFS machine has a volume display on the HMI (human-machine interface), but that number is just a measurement of the cavity or cup, not the actual product inside the bag. For solids, weight is the only reliable way to confirm fill volume, because even a perfectly measured volume can be light or heavy based on product density. Once you make an adjustment to the filling mechanism, you need to calibrate against a checkweigher, not the machine\u2019s internal counter. Here\u2019s my go-to calibration process, which I\u2019ve refined over years of on-site support:<\/p>\n