A machine builder in Poland called me last month. Eight stations, one second per index, bottle filling line. He had already picked a globoidal cam indexer from a catalog before asking for a price. Then I asked for the load torque and the dwell time, and the conversation stopped. He had not calculated either one. That is the most common mistake in this business, and this guide is built to stop you from making it. A globoidal cam indexer is a precision part, not a commodity, and the difference between a good quote and a bad one starts with three numbers: stops, torque, and accuracy. Get those right, and the globoidal cam indexer you order will run for years without a phone call to the factory.
Send these three numbers, or the quote means nothing
Before you ask any factory for a price, send three numbers. The stops, the number of stations your dial actually needs, because the cam profile is fixed at the factory and cannot be changed later. The torque, total load at the output flange, dial weight, fixture weight, part weight, and the radius to the heaviest one, because that is what decides the frame size. And the accuracy target, because a standard globoidal cam indexer holds around plus or minus 30 arc-seconds, and tighter grades cost real money. Skip these and the supplier quotes a size that covers their risk, not your line. A supplier who asks for your load numbers before pricing is doing you a favor. One who quotes from the table diameter alone is guessing, and you should treat the quote exactly that way.
How many stops, and what does the dwell do
Stops are set at the factory, so get this right first. The standard range covers 2, 3, 4, 6, 8, 10, 12, 16, 20, and 24 stations, and you pick the number that matches the process, not the prettiest catalog page. A six-station dial for a process that needs eight means one station sits idle on every unit you buy. The dwell angle matters too, because it is the time the globoidal cam indexer holds the output locked while the machine works, and a longer dwell gives the line more working time at the same cycle rate. Tell the factory the stations and the working time per station before you ask for anything else, because those two answers decide the cam curve, and the cam curve decides whether your globoidal cam indexer runs smooth or jerks through every index.
Why the same size costs so differently
The same frame size is quoted at wildly different prices, and both suppliers swear they are right. Here is what sits inside the gap. Cam grinding first. A factory that machines the cam in-house controls the profile, the surface finish, and the quality drift, while an outsourced cam is a wildcard in every batch, and the globoidal cam indexer is only as good as that grinding. Bearings are second. The roller followers carry the whole load through millions of cycles, and cheap followers show up here first. Housing and treatment are third. Cast housings with proper stress relief and hardened cam surfaces survive continuous running, and budget builds do not. Freight and lead time are fourth, and on a heavy cast unit they can add a real percentage to the landed cost. So when a quote looks suspiciously low, ask where the cam is ground. When it looks high, ask what you are paying extra for.
The numbers that decide if it lasts
Positioning accuracy is the first number to check, sometimes called indexing accuracy, and a quality globoidal cam indexer holds around plus or minus 30 arc-seconds, with tighter grades at plus or minus 15. Repeatability is the second number, how consistently the unit lands on the same position cycle after cycle, usually plus or minus 5 to 10 arc-seconds on a good unit. Torque rating is the third, and it is only meaningful when you know the duty cycle. Service life is the fourth, and the honest way to compare is the rated cycles at full load, not a vague promise of years. Any supplier who cannot explain the difference between positioning accuracy and repeatability does not understand their own product.
Flange, shaft, table, or hollow: pick the one that fits your dial
The same body comes in different output forms, and the choice is about how the dial mounts. Flange output is the default, a flat mounting face with a center bore, and our flange cam indexer range covers the common sizes, and it suits most rotary assembly tables. Shaft output couples through a protruding shaft to your own dial, and it gives more freedom for custom table design. Table-type units come with the table built in and are the fastest to install. Hollow units pass cables, air, and vacuum lines through the center, often the deciding factor on automation lines. Match the output to how your dial is built, not to what looks sturdy. When you compare output types across brands, keep the datasheet numbers side by side, because the same frame size can carry very different torque ratings from one globoidal cam indexer maker to the next. The right output form for your dial is the one that keeps the globoidal cam indexer centered under the load.
Screen the factory before you send money
The unit price matters less than the factory behind it, because a failed globoidal cam indexer stops your whole line. Ask whether they machine the cam in-house, and ask for a video call to the grinding shop. Ask for the inspection report on the actual unit, not a brochure, and get the accuracy numbers in writing. Ask about the housing material and the cam surface treatment, because both decide how long the unit survives at full speed. Ask what the warranty covers and who pays the return freight if a unit fails. A factory that answers all of these with documents is a factory worth talking to. One that only quotes a price is a factory to walk away from.
Quick answers on globoidal cam indexers
How long does one last? A well-maintained globoidal cam indexer runs for years of continuous operation, and the cam and followers are designed to outlast the machine around them. Can it run fast? Yes, much faster than a Geneva mechanism, because the cam profile controls the acceleration curve instead of relying on impact. Does it need a servo? No, a simple AC motor with a brake or clutch is enough, which is part of why a globoidal cam indexer is cheaper than a servo table. Can the index angle be changed later? No, the cam profile is fixed at the factory, so the stops and the angle must be decided before you order. Is it accurate enough for precision work? At plus or minus 30 arc-seconds or tighter, yes, and that is why the globoidal cam indexer is the default for high-volume production dials.
Send your numbers, get a unit that fits
A globoidal cam indexer is only as good as the numbers you send before the order. Send us your stations, your index and dwell times, your load weight and radius, and your accuracy target, and our engineers will size the unit, pick the cam curve, and confirm the output type before you commit. That is the standard way to buy a globoidal cam indexer from a factory that cares about the fit. Our cam indexer range covers flange, shaft, table-type, and hollow outputs from 2 to 24 stops, with standard 30 arc-second accuracy and tighter grades on request. Check the cam indexer product pages for the size tables, or send your application details through our inquiry form, and get a quote built on your process, not a guess.