WeTeamUp Terms: “Collet”

Collet-and-tool

What’s a “Collet”?

[kol-it] – Noun

The collet is the mechanism that holds the milling tool in the spindle during operation. It transmits the spindle’s power into the tool while keeping it precisely centered under milling loads. In dental milling machines, the collet opens and closes to allow for tool a changes during milling.  A properly functioning collet is essential to trouble free dental milling.

Interesting Details about Collets:

  • Collets require regular care.

A dirty or worn collet doesn’t work correctly. Make sure you’re aware of the proper maintenance recommendations for your milling machine’s collet. It’s common for them to be neglected. Sometimes the pressure of production makes it easy to forget to care for your machine’s collet. Keeping your collet clean, inspected, and in overall good health will help you avoid common milling issues like chipping and premature tool wear.

  • Collets wear out.

The life expectancy on a collet will vary from machine to machine, but they all eventually wear. A worn collet will suffer from reduced clamping force and will fail to hold the tool perfectly centered. A poorly performing collet will increase the amount of tool runout you have. Typically worn collets will be accompanied by heavy tool wear and lots of margin chipping.

  • Sub-par tools can reduce collet life.

Tools and collets must be precisely matched dimensionally. Lower quality tools can be under or oversized. Any inaccuracy in the roundness of the tool will be translated to the collet and cause excess wear. Keep this in mind when you’re calculating the cost of your tooling options.

  • Check your collet first.

If you’re experiencing milling issues, it’s likely caused by a dirty or used up collet. It’s always less costly to replace a collet than your spindle. It’s good practice to rule out collet issues first when trouble shooting milling issues. In fact, we recommend keeping brand a new one in stock for this purpose. Having the part on hand can help get you out of a bind quickly.

Thanks for reading! We hope this break down of the term “collet” has been of value. Stay tuned next week for another post like this!

 

 

 

 

Blog Series: WeTeamUp Terms

WTU-Terms-Intro

WeTeamUp is starting its new blog series “WeTeamUp Terms”

The new series will take a comprehensive look at terms that matter to those of us involved in dental CadCam.

Most of us reading this site are dental lab techs looking to become more knowledgeable. A good portion of our readership are new to dental CadCam, both technicians and lab owners alike. Starting off with digital can be a daunting task. WeTeamUp wants to try to alleviate that stress.

One of the most challenging aspects of learning dental CadCam is becoming familiar with the jargon. That’s how we came up with the idea for this new series. Over time, we will create a nice sized library of terms that will be an enduring resource for the digital community.

Every post we will pick a term that’s common in dental CadCam production and break it down. The posts will be easy to digest, quick reads that are 500 words and under. The idea is to be able to read a post within a few minutes and gain some insight, then go about your day.

Each post will be comprised of two sections. The first section will have a simple overview of that week’s term. Following that, the second section will be a bullet point list of interesting details to remember.

WeTeamUp terms has it’s own category, you can see all of the term posts HERE

We’ll also update a list of posts below:

Hopefully, we can teach you something along the way and improve your digital knowledge base.

Stay tuned!

WeTeamUp Terms: “Spindle”

WTU-TERMS_Spindle
WTU-TERMS_Spindle

What’s a “Spindle”?

[spin·dl] – Noun

The spindle is the business end of the dental milling machine. The term “spindle” refers to the mechanism that provides the power for the cutting tool. The spindle spins the cutting tool at high speed and supplies all the cutting force required for milling. If someone is talking about a spindle, they’re talking about the entire rotating assembly that holds the tool. This usually includes the spindle motor and tool changer mechanism.

Interesting Details about Spindles:

  • Spindles are costly wear items

Unfortunately, spindles wear out. It’s usually the costliest repair that we do on our milling machines. Depending on the machine they can cost up to $10k to replace. Be sure to consider this cost when you’re shopping for a milling machine. You can count on it coming up at some point – usually outside of the machines factory warranty.  To prolong the life of your spindle, make sure to maintenance your machine regularly.

  • How hard is it to replace a spindle?

The difficulty of the job varies from mill to mill. The cost of a service call to replace your spindle can be huge, and it’s on top of the cost of the part.  When you’re shopping for a machine ask if the spindle is user replaceable. On some mills, you can change it yourself in minutes. This can be a huge cost savings for labs willing to get their hands a little dirty.

  • The number one killer of spindles is bad compressed air

Most spindles utilize compressed air to cool their bearings. In fact, many of them run air directly past the high precision ceramic bearings. If the air is dirty or wet, it can corrode the bearings and greatly reduce the service life of the spindle. If your spindle is air cooled, it’s a must to invest in proper air filtration and drying.

  • Spindles come in all shapes and sizes

They can vary greatly in terms of power output. Some dental machines have as little as 100 watts of spindle power output, while others can range into the kilowatts. Spindle power output is correlated to machine cost. More power costs more. Machines designed to cut hard materials like titanium require much more robust spindles to get the job done. This is a major driver of the cost difference between desktop mills that are meant for soft materials and the more “industrial” breed of machines capable of milling hard materials.

  • Spindles and tool changing: Different schools of thought

Dental milling processes require several different sized tools to accomplish the job. Most dental milling machines utilize a tool changing mechanism that’s build into the spindle. Other designs use either multiple spindles or an externally mounted system. The way the manufacturer goes about this design decision impacts the cost and complexity of a spindle repair. As a rule of thumb, the simpler the better.

  • When the time comes: Rebuild or replace?

Many of the higher end spindles are rebuildable. You can save a major portion of your replacement cost by using a refurbished unit. If you utilize factory refurbishment, or the services of a reputable rebuild shop – the spindle will perform like new. If you’re a higher production lab, it might make sense to have a spare on the shelf ready to swap out. This move can save days of down time.

Thanks for reading! We hope this break down of the term “spindle” has been of value. Stay tuned next week for another post like this!