Techno CNC Tooling

CNC Tooling and Accessories

Apr 18

Vacation

To all- I am away on vacation this week. Tune in next week. Same cutter channel, same cutter time. Happy Easter to all!


Apr 10

Miss Collet fights back!

Router Bit Ray:

I would like to welcome you to the show Miss Collet. I understand you would like to have your chance at a brief rebuttal from my last interview with Mr Ballnose.

Miss Collet:

Yes. Thank you Ray. After reading your last interview I felt that I had to talk with you immediately.

Router Bit Ray:

Fire away. That’s what I am here for. Equal Time.

Miss Collet:

For one thing I would like to say that in the beginning my relationship with Mr. Ballnose was unbeatable. Cutting away with ease. Extracting chips was always in an upward direction always leaving a mint and smooth cut. Yet as time went on in the 500th hour, things started to slip away.

Router Bit Ray:

Go on

Miss Collet:

Well. I honestly felt used towards the end. Mr Ballnose was getting all the credit for the final product where in the end we were really both a team. (tears began to fill her eyes)

 Router Bit Ray:

(Being the sensitive man I am, I offer Miss Collet a tissue and a small hug of encouragement.)

Miss Collet:

Thank you Ray. There are not too many like you. All cutters are pigs!!!!

Router Bit Ray:

I beg to differ on your cutter opinion. I happen to love all cutters. They are my bread and butter. No use for the dull ones however.

Miss Collet:

Sorry, I have been too emotional sometimes recently (Sob, Sob)

Router Bit Ray:

What can be done to help you out.

Miss Collet:

All I need is a little respect.

Router Bit Ray:

R-E-S-P-E-C-T?

(No Response)

Sorry, I may be sentimental yet my dry sense of humor tends to offend sometimes. I don’t mean this to happen, it just does. Enough about me. Go on.

Miss Collet:

Thank you. All I ask is to be cleaned after each tool change and not with with a petroleum based lubricant as it will ony act as a magnet for all the dirt and dust and speaking for all collets it gets pretty messy. Check for any abrasions or markings and change me often. This will give you longer tool life and a better cut in the long run.

 Sometimes I am misunderstood yet my feelings are very temperamental. A clean collet is a happy collet. It is not always about the cutter. Talk to Ms. Toolholder. She will back me up on that.

Router Bit Ray:

Thank you Miss Collet. I wish we had more time yet I have to keep my interviews at a minimum. No one likes to read these days. Too much multui-tasking with nothing really getting done if you know what I mean. But that is a different subject for a different time and blog. I hope you got your opinion in the way you wished.

Miss Collet:

I thank you for the opportunity. I still have much to defend myself against Mr. Ballnose. Maybe another time.It was a pleasure. Please remember me and all collets are vitally important for a nice cut.

Router Bit Ray:

I will. I promise. I am not that kind of guy. Till next time.


Apr 5

Interview with Mr. Ballnose cutter

Router Bit Ray:

Welcome to the show Mr. Ballnose cutter

Mr. Ballnose cutter:

Hello nice to meet you!

Router Bit Ray:

I am glad you took time out to speak to us. Can you give a brief history of your life

Mr. Ballnose cutter:

Well I was always a smooth kind of guy. I was always rounding off things as a kid. Hated sharp corners. My mom would always make me stay straight and narrow during my adolescence. I would not just round off my numbers in math class but also my bedroom dresser. I was part of a bowling team in high school which did not last too long. Always went for the gutter ball.

Router Bit Ray:

Very funny.

Mr. Ballnose cutter:

My first job was in a sign making  company located in Ronkonkoma, N.Y. All of the signs made there were very nice however I recommended adding more detail by smoothing out and adding a little detail. At first all the chips were hitting me in my face yet when I converted my religion to an upcut spiral I started to expel the chips outward and quick. After the company saw this I was promoted and found my calling in life.

Router Bit Ray:

I would think your career decision was a very good one.

Mr. Ballnose cutter:

Oh yes. Now I am used for carving, decorative doors and foam cutting. The foam is what I love the most. Smooth cutting and a long life of easy routing. Not a very dense material yet a nice break.

Router Bit Ray:

How about your experience with other materials?

Mr. Ballnose cutter:

I graduated to soft and hard woods, composites, soft and hard plastics even aluminum and solid surface.

Router Bit Ray:

What are the undesirable aspects of your job?

Mr. Ballnose cutter:

Most definitely when I am not cleaned off after I am removed from my very good friend Miss. Collet. We have a very strong relationship yet when we are both not cleaned up after working together we can really rub against each other. When this happens things start to slip and nothing goes right. Sometimes I actually break and I need replacement which can put all of us in a jam. By this I mean myself, Miss Collet, my boss and worst thing our customer.

Router Bit Ray:

The customer does really matter most. We are running out of time because this was meant to only be a quick interview. One more question. Are you and Miss Collet still getting along?

Mr. Ballnose cutter:

I am a Happy bachelor which is what I prefer. I get in a new collet relationship every 400-500 hours of working time. I can’t stand when I see those nasty abrasions and chip dust build up on the inside of a collet. They look old and used. Sure I have the same thing happen to me. I know life is not fair yet the router bits tend to age better. Almost like a “good wine with age” the cliche says. I’m not a chauvinist just a realist.

Router Bit Ray:

Well thank you for your time. I hope you enjoyed the interview.

Mr. Ballnose cutter:

Thanks it was a good one. Went real smooth!


CNC cutting tip of the day

http://www.techno-isel.com/tooling/tips.asp

Bits


Feed and Speed chart

Here is a feed and speed chart for CNC routing. This will guide you to setting up the proper feed rates when cutting various materials.

http://www.techno-isel.com/tooling/0335_FEEDSandSPEEDS.pdf


Apr 1

Trouble shooting tool breakage problems (Part one)

The router bit is the weakest part of the routing system. When it breaks it is usually the first thing that gets the blame, which does not always hold true. Tool breakage can be attributed to three factors.

1. Improper tool selection

2. Poorly maintained equipment (Collets, collet nuts, spindle bearings etc.)

3. Poor fixturing

One should examine the shank of each tool after every tool change. Look for “collet burn”. This will show as brownish, burn marks on the shank of your tool. I recommend changing your collets every 400-500 hours of operating time.

Also try to use a tool with no step down. What I mean by this is keep the shank diameter and the cutting edge dia the same as much as possible. As this will give you more rigidity and less chance of snapping in half. This is not always possible yet should be implemented.

Another common error is excessive cutting edge length. Use the shortest cutting edge length to achieve depth of cut. Many shops try to save money by using one bit for different thicknesses of materials and end up breaking a bit when going with an extremely long cutter on very thin material.

http://www.technocnc.com/


Mar 23

Does anyone need help with router bit cutting applications?

  • Please feel free to reply with any questions you may have regarding CNC cutting tools

Mar 12

Take Time out to see what a Techno CNC router can do for you.


Oct 1

Collet sale

What a excellent sale!!!!!!!!!!!!!!!!

All ER32 and ER25 Collets normally $39.95 are priced at $16.95 each

Take time out and Visit http://www.techno-isel.com/tooling/Accessories.htm for details.


Jun 23

Be Kind To To Your Collets

 

This week I am releasing a sale on our collets. It will be a 2 week special and all size collets will run for $16.95 each. Including metric. I feel it would be a good way for anyone to stock up on collets because the run time is typically 400-500 hours run time. If you change your collets on a regular basis this will enhance tool life and protect your spindle at the same time.

Here is a great article on caring for your collets which will be beneficial to anyone who desires a high quality cut and finish they desire.

 Collet toolholders are too important to the machining process to use them incorrectly. Follow this simple advice.

The way a collet was designed to be used usually differs from the way that collets are used in practice. This is unfortunate given the critical role that collets play. A collet is the wedge between the toolholder and the cutting tool. This wedge, not the toolholder itself, is what does the actual tool holding. By gripping and positioning the tool, the collet determines both clamping force and runout, and therefore it can also determine the very ability of the process to produce a good part. Improving how well collets are used and cared for is an easy way for the shop to make better use of its tools. This article offers some simple advice.

Perhaps the simplest advice of all relates to the detail that is most often overlooked: cleaning. Collets are coated in a thick, rust-prohibitive oil before they are packed and shipped. This heavy coating may be great at preserving the collet, but it’s horrible to leave on during use. The oil reduces gripping force and may also affect runout.

To remove the protective coating, spray collets with a thin cleaning oil, such as WD40. Usually, the collet can then just be dried with a towel.

If the collet has been in use for a while, it may have picked up deposits on its tapered areas. The deposits can be the result of dirt in the toolholder, workpiece material getting into the collet cavity, dirty coolant or even the burning of any oil that was left on the collet’s surface. When trying to remove one of these deposits, avoid implements that will remove or deform the collet’s metal. A simple, lightweight brass brush is probably the best cleaning tool to use. This can be used with or without a cleaning agent. If the deposit can’t be removed this way, then it’s time to replace the collet. Foreign matter on the collet that is big enough to see will affect how well the collet performs.

Clean the inside of the collet as well. The same light oil such as WD40 also works here. After cleaning, visually inspect the ID for any debris or signs of damage.

Finally, clean the slots. The slots provide the collet with its ability to collapse and hold the tool, so anything inside a slot that gets in the way of this collapse will reduce the clamping force and increase runout. Thoroughly clear the slots of debris using a thin metal or plastic blade.

Signs Of Misuse Or Damage

After cleaning the collets, check them for signs of misuse. This inspection takes only a moment and can usually be done during the toolholder assembly process. Here are the signs to look for:

Is there a gouge around the nose of the collet? This means the collet and nut have been assembled incorrectly. The collet can’t be fixed once it has been damaged this way.
Is there a deep line around the collet gage line? This indicates the tools have not been inserted to the minimum depth required for clamping.
Has the collet lost roundness? Either in the hole or around the outside form?
Are there burrs on the collet?
If the answer to any of these questions is yes, then replace the collet.

What Can Cause Poor Runout?

After cleaning and visual inspection, proper assembly of the toolholder is the next important step. There are various ways that even a good collet can contribute to poor runout because of some aspect of the toolholder assembly. Here are the most common problems my company has seen:

1. Improper collet-to-nut assembly. In an incorrect assembly, the collet is placed in the holder first, then the nut is clamped on. In a correct assembly (pictured in the photo at the beginning of this article), the collet goes into the nut first, then the tool is inserted and then the nut is screwed onto the holder. The incorrect assembly can cause runout as high as 0.001 inch.
2. Not inserting the tool deep enough into the collet. For every collet there is a rated minimum tool depth. If the tool is clamped in place at a more shallow depth than this, runout will occur as the collet deforms incorrectly.
3. Over-tightening the nut. Turning the nut too tightly will also deform the collet in a way that leads to poor runout.
4. A bad pull stud. The pull stud, or retention knob, is screwed in at the end of the toolholder’s taper. In a case where this stud or knob was worn, the author has seen a runout of 0.001 inch. Replacing the stud (and making no other change than this) brought runout down to 0.0001 inch.

How To Get Better Runout And Higher Clamping Force At The Same Time

So much for the possible causes of poor runout. What can the user do to actually improve the collet toolholder’s performance? Here are some tips:

1. First, clean the assembly—not just the collet, but also the nut and holder.
2. Put a light coat of oil on the outside of the collet. There should be enough oil to coat the collet, but any excess is too much. The purpose is just to reduce any friction between the collet and the toolholder when the collet is pushed into the cavity. A collet that slides more easily lets the nut apply more of its torque toward pushing collet into the holder and closer to the centerline. The result is better runout and higher clamping force.
3. Make sure at least 2/3 of the collet’s gripping surface is used. If the tool is not inserted to the collet’s minimum depth, then an improper deformation of the collet will lead to runout. Failing to use the correct depth will also fail to capture the amount of shank required for the collet to achieve its intended gripping force.
4. Make sure the tool isn’t pushing against a metal backup screw. Some holders provide this screw as an adjustment aid to set the tool length. This screw can get in the way of holding the tool as securely as possible. The problem arises when the collet is free to move slightly during toolholder assembly, but the tool is constrained against this screw. The resulting friction between the moving collet and the stationary tool can reduce the clamping force. Our studies have shown that it can reduce the force by up to 50 percent.
5. Using a tool with a Weldon flat can also bring about a lower clamping force. While a tool with a Weldon flat can indeed be used in a collet, the tool will see less clamping force by up to 30 percent—or just about the same area that the flat takes up along the clamping length.
6. When tightening the nut, torque down on it only to the value specified for this nut. Use a quality torque wrench to observe this limit. Exceeding the torque does not provide more clamping force; it just leads to runout. In fact, the more force is applied, the more the top of the collet wants to twist with the nut. Too much force can actually twist the collet’s top, deforming the collet, which will increase runout and reduce clamping force.
7. Avoid this collet-twisting phenomenon by using a nut that reduces the friction between the nut and collet. Different varieties of nuts achieve this low friction using an impregnated coating, a ball bearing or a friction bearing.

Collet toolholders are ineffectively used in many shops. By following all of the advice above, a shop can realize greater holding strength and better precision from its collet toolholders than what many shops are able to achieve.

 


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