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In a subcontrator’s view, its latest mill/turn centre stands out for its powered tooling ability to mill and drill and in particular, through the added flexibility from its two Y-axis cross feeds.

With seven Citizen CNC sliding head automatic lathes already fully occupied and capacity filling fast on the most recent pair of Citizen L32 mill/turn centres installed at HPC (Services) of Ilkeston in Derbyshire, managing director Paul Cobb decided a detailed review had to be made of the type of components and in particular, the amount of milling required in the future.

Only then he maintains, would he make the decision to look for extra machines.

As a very timely result he explains: “We decided to go along to the NC Engineering open house and see first-hand what Citizen could provide.

Our review had already highlighted how milling was becoming more and more important on ‘one-hit’ cycles so high levels of milling and turning flexibility had to be at the top of our agenda.” In Cobb’s view, the new Series 3 version of the M32-V stood out for its powered tooling capability to mill and drill and in particular, through the added flexibility from its two Y-axis cross feeds, one to the turret and second to the gang tool slide.

“So we bought one,” he says “as well as a Citizen L20-VIII.” Cobb describes how his setters cannot believe how the metalcutting efficiency has improved with the new M32.

He says: “We are getting parts from the machine at least 25 per cent and, in some cases almost a third, faster which is proving very beneficial in helping to meet cost-down targets of certain of our customers.” The new M32 machine has not only freed up capacity on the existing Citizen L32s at HPC by enabling more complex work to be transferred resulting in shorter cycle times, there is more.

As he outlines: “With the additional Y-axis we can very quickly electronically adjust tool centre height bringing it exactly on centre line which speeds up our setting.

In-cycle tool change is now much quicker with the new Citizen tool holders you just program a Y-axis move of the turret sideways to the next tool and save an index.” However when it comes to milling - the prime motivator for the purchase, “We can get a lot of very complex milling and drilling performed on a component in the subspindle for free, in terms of cycle time, while still machining away at the main spindle.” The fact that setters no longer have to contend with polar interpolation to produce a flat on a part, for instance, is another bonus.

“We just come in from the side with the tool and mill across the job with the added advantage of using the bottom of the cutter and not the edges.” Maintains Cobb: “We reckon the latest Citizen M32 is the most highly developed machine of its type for producing the class of parts we make up to 32mm diameter.

More and more we are exploiting the machine’s configuration of tooling and axes to machine not only brass and stainless steel components but also aluminium and plastics.” Very effective cutting cycles that could never have been considered before include taking large cuts, up to 10mm deep, by simultaneous twin turning the same diameter from 25mm down to 15mm in stainless steel at 0.12 mm/rev.

Previously, multiple single cuts at 0.03mm/rev would have been taken so the new method has saved over one minute floor to floor time on one component alone.

Then there is the added bonus of reduced idle times from the faster processing of the new control which reduce cycles further.

“When you have a batch of several thousand to run - these are savings really worth making,” he says.

Cobb then adds comments on the latest specification LNS Express 332 barfeed fitted to the sliding head machine.

“Changeover is much quicker and the split block arrangement is far superior to other barfeed designs giving better support to the bar and enabling higher, up to 8,000 revs/min spindle speeds, to be used without any vibration.” HPC employs 50 people and has seen order books swelling month on month from customers in the luxury goods, printing and domestic appliance sectors.

By setting the business to provide a prototyping service, this now accounts for about 10 per cent of the business.

Production and sub-assembly services, as well as a strong design for manufacture consultancy and component development capability, has meant a build-up of a very loyal partnership with a relatively small band of regular customers.

But central to the philosophy of the business is Cobb’s contract machining component superstore theory.

Although it means risk because completed parts are held in the finish parts store for customers to simply call-off when required, it has created three major advantages.

Firstly, customers can enjoy a next day delivery service which pretty well eliminates panic jobs, the scourge of production schedules, but most important, allows Cobb and his team to plan for maximum machine utilisation and efficiency of changeover.

In short, HPC’s machines are producing through three shifts a day over a six days a week with changeovers performed when it is convenient to them! “The spin-off,” maintains Cobb, “is that we are generating profits from sales of over GBP 5 million a year that are ploughed back in the business and we are steadily installing new equipment.” In the first half of 2003, GBP 500,000 was spent, the end of the year a further GBP 550,000 was committed which included both the new Citizens.

For 2004, similar investment plans have been laid and funded in order to maintain ‘The edge’ over competitors in the UK and especially those from overseas that are trying to attract supply contracts against lower pricing.

“If we can maintain a competitive edge through technology and help customers with ‘cost down’ programmes we have found they would rather buy from a known UK source they can work very closely with and one that fully understands the requirements.

It is not all price wars - the benefits of trust in a supplier still holds water providing the supplier does not get complacent and begins to let customers down.”.

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Composites are becoming increasingly common in aerospace applications, and machining new materials can be a challenge for shops used to cutting metal. One such substance, carbon fiber-reinforced plastic (CFRP), can be difficult to drill because tools often “push” through the material rather than executing a clean cut. To address this issue, cutting tool manufacturer OSG Tap and Die has developed a carbide drill featuring specially engineered geometry and a custom diamond coating method that keeps the tool sharp.

Similar to Fiberglass, CFRP is a tough, abrasive material that can quickly wear cutting tools. The material—which, incidentally, makes up much of the fuselage of Boeing’s 787 Dreamliner—is stronger yet lighter than aluminum. To machine CFRP, shops commonly use long-lasting diamond tooling such as PCD insert drills, vein PCD drills or brazed mandrel tools. According to OSG, however, many such cutters can still have a tendency to rip apart the composite layers rather than shearing cleanly through. This can leave unsightly tear marks and compromise the material. The company says such tools may not incorporate the proper relief geometry and edge design to prevent this phenomenon, which is known as “delamination.”

Designed specifically for CFRP applications, OSG’s new drill features larger relief angles for sharpness and chamfers and/or radii on the corners to avoid wear. Beyond these common features, the drills are specially designed for each customer because different geometries are more or less useful depending on the type of CFRP, which is commonly layered with other materials. For example, the company might recommend a variation on a double-angled drill design for a shop machining CFRP embedded with titanium.

Like other cutters commonly used in composite applications, the drill incorporates diamond to extend tool life—a particularly important consideration when machining a tough material like CFRP. In this case, the diamond is a coating applied via chemical vapor deposition (CVD). However, coating applied to a tool or insert often rounds the cutting edge and offsets any tool-life gains by reducing sharpness. The duller the tool, the less likely it is to make a clean cut and avoid delaminating the material.

With this in mind, OSG has developed a custom coating application methodology that keeps the micro-grain structure of the diamond crystals to less than 1 micron. This allows the coating to conform more closely to the contours of the cutting edge, providing the necessary tool life improvements while maintaining sharpness. The custom process involves intensive cleaning and preparation of the carbide tool before applying the diamond coating. The company chemically etches each tool for coating adhesion, while a series of chemical baths control the quantity of cobalt, a material inherent to the carbide substrate. This is important because too much cobalt can cause graphite contamination of the coating, which can result in chipping or flaking issues.

While PCD tools last longer than the CFRP diamond coated drill, OSG says they are more expensive because of the costs involved in their production. Additionally, the small micro-grain structure of the drill’s CVD coating is said to keep the tool sharp, enabling a single tool to cut a hole in CFRP. According to Drew Strauchen, engineering and marketing manager at OSG, this can be advantageous for shops used to employing multiple tools to remove as much material as possible before breakthrough to the other side of the hole, when most delamination occurs.

“When drilling composites, our customers are generally used to drilling the hole in several steps, sometimes using three or four drills to produce one hole,” Mr. Strauchen says. “With ours, they can use one or possibly two drills, saving money and reducing the number of tools in the process.”
http://www.mmsonline.com/articles/drill-deletes-delamination-in-cfrp.aspx

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Shops commonly outsource non-machining operations because the envisioned cost and learning curve make it seemingly impractical to bring those processes in-house. They’d rather leave heat treating, laser welding and other such processes to vendors with the expertise and the right equipment, and concentrate on their core compentency—machining good parts.

Anodizing is a process that shops often outsource because of these reasons. In addition, it is likely that they are unsure about the anodizing process itself as well as regulatory, safety and environmental issues (some of which vary from state to state). That said, shops can realize considerable cost savings by bringing anodizing in-house. In doing so, they will gain direct control over quality and delivery time while alleviating logistics headaches, too.

So, how do shops know if adding anodizing is right for their situation? One way to determine this is to contact designers and builders of anodizing systems. IPEC Global (Ontario, California) is one such company. Ken Emilio, company president and CEO, has owned and operated machine shops for years and has created a number of anodizing lines for shops. The information he provides in this article offers an overview of anodizing fundamentals along with practical information for shops that may be at the very early stages of anodizing investigation. Although this article isn’t meant to be a “how-to” piece, it does answer initial questions shops often have about the feasibility of adding anodizing to their list of manufacturing capabilities.

What Is Anodizing?
Anodizing is an an electrochemical process that speeds the natural oxidation of select non-ferrous materials. It improves material surface hardness and wear resistance, and it allows users to manipulate oxidation thickness. Aluminum and titanium are the two most common materials shops are likely to encounter that require anodizing. Anodized components are used for a variety of military, medical, commercial and automotive aftermarket applications.

Anodizing also enables users to change a part’s color using dyes (in the case of aluminum) or manipulating electrochemical parameters (for titanium). For some applications, this color may be simply for aesthetics. For others, such as medical devices, specific colors are chosen for identification purposes. The color of a medical screw, as an example, may dictate the screw’s thread dimension and diameter. This color coding also helps with inventory control, making it unneccessary for hospital employees to be familiar with fastener nomenclature or dimensional identification.

There are three types of aluminum anodizing. Type I anodizing, which uses a chromic-acid-based chemical bath, is commonly used for applications that require a thin, protective coating and a high level of corrosion resistance. It also serves as an effective primer prior to painting or other coating operations.

Type II anodizing is the most common and often the most affordable aluminum anodizing process to bring in-house. It is used on a wide variety of applications and enables parts to be dyed in virtually any color. It is based on a sulfuric-acid chemical bath.

Type III anodizing is known as hard-coat anodizing. It is used when a very hard surface is needed, such as for weapons, sporting goods and bearing surfaces. Type III anodized parts typically aren’t dyed. Rather, shades of gray are achieved by altering temperature, voltage and bath compositions.

Should Shops Anodize?
To gage the appropriateness of adding anodizing, a shop should first calculate the amount it currently spends outsourcing anodizing. If that cost is less than $10,000 per year, then it’s generally a good idea to continue using the vendor as long as that vendor is dependable.

If anodizing costs as much as $50,000 per year, then installing a small, modular anodizing line makes sense. These prefabricated systems look like a series of in-line washing machines, and have all necessary tanks, ventilation and closed-loop, rinse-water recycling systems. These units range in price from $30,000 to $75,000. Securing requisite permits for these units typically is not a challenge because the chemical volumes are relatively low and spill containment and fume control are often built into the unit. Such modular anodizing lines are suited for small quantities of parts as large as 2 cubic feet, and typically have a footprint of approximately 20 feet by 8 feet. Part racks are moved manually from tank to tank with these small modular systems.

If anodizing costs $150,000 or more, then a medium- or large-scale modular anodizing line may be appropriate. These systems sometimes use a hoist to move part racks from tank to tank. Prices range from $100,000 to $150,000, and it’s recommended that shops contact an anodizing consultant to help plan line design and develop operation manuals.

Modular anodizing systems generally aren’t recommended if a shop’s annual anodizing cost exceeds $250,000. The tanks, pollution control and other related equipment will be significantly larger. Although lines of this type might cost between $250,000 to $500,000, an anodizing cost savings of 50 to 60 percent is possible. In this case, an anodizing expert should certainly be used to develop a preliminary line design before a shop solicits estimates from equipment suppliers.

Steps In Anodizing Aluminum
Parts must be immersed in a number of baths before and after the actual anodizing process. Each bath has a specific temperature, chemical concentration and immersion time that must be monitored and maintained. Proper rinsing after every support bath is essential. What follows are the typical steps for Type II anodizing of aluminum alloys. (See page 104 for a detailed list of operations for Type II anodizing of 6061-T6 aluminum.)

* Alkaline clean—Alkaline cleaning is often the first anodizing step. This bath is designed to remove grease and oils from parts without etching the parts or removing material. Alkaline cleaning is typically followed by a rinsing bath.
* Alkaline etch—This bath removes oxides and gives the parts a smooth, matte finish. An etch bath is not required when a brilliant shine is desired at the end of the process. Etch baths should be followed by vigorous rinsing.
* De-smut—The de-smut/de-oxidizer bath removes the dark smut created by the etch bath and is a critical step prior to anodizing. De-smut stations usually use nitric-acid or ferrous-sulfate baths.
* Bright dip—The bright anodizing bath, typically of concentrated nitric acid, ultimately shines and protects the part surface. This bath does emit large volumes of nitrogen oxide fumes, however, so proper ventilation is essential. Anodizing in high volumes can require scrubbers to clean these fumes before they are released into the atmosphere.
* Color—A wide variety of different colors and color patterns are possible in a dye bath.
* Seal—Anodized aluminum surfaces require sealing to eliminate color fading or running. Some sealers include sodium dichromate for added corrosion resistance.

Safety

Operating an anodizing line is similar to operating aqueous cleaning, deburring and vibratory finishing tools. That said, anodizing uses hazardous chemicals so worker safety is paramount. The types of hazardous materials shops will need to purchase, use and store include sodium hydroxide, chromic acid (for Type I anodizing), sulfuric acid (for Type II and III anodizing), nitric acid, ferrous sulfate, nickel acetate and organic dyestuffs. Obviously employees should be outfitted with the proper protective gear. For information about handling these materials, shops should contact their state’s department of environmental quality.

In addition to hazardous chemicals, anodizing also generates hazardous waste. This includes diluted wastes such as rinse water and concentrated wastes from cleaner tanks that need to be removed.

Two other areas of concern are wastewater discharge and air-pollution control. The wastewater from rinsing can be recycled or sent to the sewer if local regulations are met. Adequate ventilation is also necessary. Most modular anodizing units have integral ventilation hoods. Anodizing fumes must be exhausted outside the facility, so a corrosion-resistant exhaust fan and ducting are needed. Type I anodizing emits chromic-acid fumes and most government agencies will require a fume scrubber. Scrubbers may not be required for Type II or III anodizing.

Regulatory And Environmental Issues
Many times the regulation process depends upon the number and size of the anodizing lines. Modular, self-contained lines are generally easier to permit than large lines. Shops considering a large line should plan on spending more time and money on engineering and permits.

In many cities permits are submitted to the local fire department for final approval. Fire codes tend to focus on chemical containment and storage in addition to fume exhaust, ventilation and fire sprinkler systems. In cases of large anodizing lines, some fire departments require an extensive ventilation system with emergency generators and fire sprinklers installed within the duct work. This most likely will not be required for small anodizing systems.

Expect Some Frustration
Shops should expect problems during the learning, installation and start-up phases. For instance, it may be difficult to locate a chemical supplier in the area. Shops may also need to purchase anodizing racks or masking materials outside of their state. Simply put, anodizing lines, even small ones, are not “plug-and-play.” However, investing time and effort early in the planning stage will result in an anodizing process that is as effective as it is easy to maintain and operate.
http://www.mmsonline.com/articles/bringing-anodizing-in-house.aspx

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Response:

These coordinate systems provide three different ways to track the machine’s movements. Each has a different point of reference - or origin.
Absolute

With the absolute coordinate system (shown on the absolute position display screen), the origin is the currently active program zero point. If fixture offset number one is active (machining center), then the absolute position display will show how far each axis is from the program zero point specified by fixture offset number one. This is often helpful when verifying CNC programs - you can tell from this display the tool’s location relative to program zero.
Relative

This coordinate system allows you to set your own point of reference. It is most commonly used when taking measurements on the machine. With this display screen page, you can reset (set to zero) or preset (set to a specific value) the axis display registers. One example of when this display screen is needed is when measuring tool length compensation values on machining centers. During this procedure, you bring the spindle nose to a flat surface and then zero the Z axis register value (on the relative display screen page). After loading a tool, you bring the tool tip to the same surface. At this point the Z axis register of the relative page will show you the tool’s length.
Machine

The origin for the machine coordinate system is the machine’s zero return position - so this display screen page will always show you how far each axis is from the zero return position. It can be helpful when you’re wondering whether the machine is at the zero return position (when it is, these values will be zero).
http://www.cncci.com/resources/tips/coord%20system.htm

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A copy of your Fall issue of the Optional Stop newsletter showed up in my mailbox over the weekend. I must confess to being stumped. I do lead a rather sheltered life (24-year programmer), but I’m slightly confounded by a couple of newsletter issues.

We use CATIA V5 and canned postprocessor software. I’ve done a bit of traveling for the company (nowhere near as much as you obviously do), and all the suppliers that I’ve visited use some form of (fairly advanced) graphic programming software (mostly CATIA, NCL or MasterCam) and canned postprocessors (admittedly, I’ve visited very few Mom & Pop shops). I’ve visited with my friends from supplier management. They tell me all tier 1 and tier 2 aerospace suppliers have CATIA. So, I’m puzzled that programming in the absolute vs. incremental mode would even be an issue. Nowadays, graphic programmers generally don’t have a clue where their cutter is (in terms of Cartesian coordinates). When I first hired in, programmers were expected to verify tool paths by double-checking post output. That generation has mostly retired. Most programmers (here) can’t even read post output. CGTech’s Vericut software handles that (also at supplier shops that I’ve visited). Today, NC programming is a point & click game. With canned post processors arbitrarily set to the G90 mode (individual programmers cannot influence this decision). So, I’m surprised this is even an issue. I read several trade journals, and don’t recall stumbling across anything about shops still ‘hand programming’ or even wide-spread use of conversational controls (we don’t have any, and I’ve never seen a tier 1 or tier 2 shop that did).

Lawrence Reimer
Response:

Lawrence,

The newsletter article (entitled G code primer: Try not to think incrementally here) was aimed at entry-level manual programmers that write programs at G code level - or at least people learning how G code works. I should have made this more clear in the article. Since these people must develop all coordinates that go into their programs (your CAM system is doing this for you), they must correctly program each position through which the tool must move for the entire program. And while working in the incremental mode will have no adverse affect as long as motions are correct, it can be confusing to work in the incremental mode.

This is why I recommend that manual programmers work predominantly in the absolute mode. Since a CAM system doesn’t get confused in this fashion, and since motions at the machine will be identical regardless of which mode is used, the incremental/absolute concern doesn’t apply. Indeed, many CAM systems that work with three dimensional shapes (like I assume yours does) will output incremental motions since programs can be kept shorter.

There are still many CNC-using companies that have not taken CAM system usage to your level. While almost every company has and uses some kind of CAM system, believe it or not, many still generate at least some programs manually - especially for simpler work. Or at the very least, they commonly edit programs at the machine. In these cases, a knowledge of G code is still important.

Second question: This question was raised from the article Macro Maven: Bar puller macro with bar replacing alarm included here.
> The other puzzle is parametric programming. I’m far from smart enough to realize how this (albeit handy) technique could be applied to graphic software / canned posting type of shop.

Response:

I know most high level CAM system programmers cringe when the topic of CNC control based parametric programming comes up. Most need “clean” output that will run in CNC controls without modification - and if misapplied - some applications for parametric programming can really gum up the works.

Keep in mind that there are five application categories for parametric programming and I’d agree that at least some are not appropriate if a CAM system is being used to generate CNC programs. Let me list these five categories and make some comments. There are exceptions to just about everything I’ll say, so remember that these are just general comments.

1) Part families - One parametric program is used to machine several parts - operator changes variables at machine to describe part being machined

Most CAM systems also offer part family programming capabilities, and since many CNC users don’t want operators in control of programming, machine based parametric programming for part families is not a good application for most CAM system users. There are some exceptions, but I don’t think they’d apply to you - so I won’t elaborate.

This tends to be the “classic” application category for parametric programming. Indeed many people think it’s the only one, feeling that if you don’t have part families, you don’t have application for parametric programming. It also tends to be the one that gums up the works the most for CAM system programmers. Shop floor people love the idea of controlling their own destiny. They’d love it if they could just change a few variables to make a different part. In reality, many part family applications are too complex to feasibly handle with parametric programming, especially when a good CAM system is available.

2) User created canned cycles - a series of motions can be executed from one G code level command

Most CAM systems will take advantage of CNC control based canned cycles (like hole machining cycles on machining centers - G81, G84, etc.) That is, the actual posted output will include canned cycle commands - they’re part of the post.

The advantages of these built in CNC control based canned cycles, of course, include shortening programs and making it easy to modify programs at the machine.

If your company performs a given type of machining operation on a regular basis - but the operation is not handled by a control based canned cycle, it may be helpful to “create” your own canned cycle and modify the CAM system’s post to output the appropriate command/s to invoke it. A classic example is with thread milling. Many CNC controls still don’t have a thread milling canned cycle. One can be easily created with parametric programming. Once created, it will afford all benefits of any other canned cycle - and again - can be invoked by the CAM system. At the machine, the program will be shorter - and the operator will have better control of how the thread is milled.

3) Utilities - the machine’s behavior is enhanced in some way

The example shown in the Fall 2007 newsletter (the bar puller counter) is a utility application. We’re having the machine automatically keep track of how many workpieces have been run from the bar so an operator won’t have to stay at the machine and count them.

Applications in this category can be helpful to any CNC-using company - including those with CAM systems. Generally speaking, any time you’re having a problem at the machine - of any kind - is a time when you should think about enhancing the machine’s behavior with a utility parametric program. This may sound like a bold statement - and of course, not all problems can be overcome with parametric programming, but it is important to consider all possibilities when problem-solving. Parametric programming provides many tools to help in this regard.

With many utility applications, the CAM system is not even involved. We’re simply modifying the way the operator works with the machine. Consider, for example, the task of measuring program zero (origin) for machining centers. If setups are qualified (fixtures keyed to the machine table), of course, there is no need for this task. Program zero can be calculated and program zero assignment commands can be included in the program. If qualified setups are not made, the position of program zero must be measured during setup. One way is to use a spindle probe (which, by the way, is driven by parametric programs). If the machine doesn’t have a spindle probe, the setup person must measure use rather crude tools (like edge finders and dial indicators) to manually measure the program zero point location.

In this last condition, the “problem” is the time and skill required. A parametric program can be used that will allow just about anything that can be done with a spindle probe to be done with an edge finder (we recommend a conductivity-type edge finder that lights up when it makes contact). The only difference is that the setup person will have to manually touch each surface (using the machine’s hand-wheel function). Everything else will be done by the parametric program.

I’ve just briefly explained but one utility application - one that probably doesn’t apply to you. But my point should be clear - when you have problems with the machine (wasted time, crashes, scrap, and frustrations of just about any kind), you should at least consider whether the problem can be solved or made better through parametric programming.

4) Driving accessory devices - like probes, tracking & reporting, and post process gauging systems

These higher-level accessory devices require parametric programming features. So if a machine has a spindle probe, it likely has parametric programming capabilities. And since the probe can be programmed, you can think of this application as similar to what was described for user created canned cycles. One or more probing “cycles” are often included within CNC programs, meaning the CAM system must be able to output the necessary commands.

5) Complex motions

Control manufacturers provide interpolation types for needed motions. Linear, circular, and helical motions are among the most common. If you encounter a motion type that the machine cannot perform, a parametric program may be the answer. (Note that many CAM systems can generate just about any kind of motion, but the program will become very lengthy - the CAM system must generate a very long series of very tiny straight or circular motions.)

Consider milling a tapered thread. This requires a kind of spiral interpolation. Even many newer machines still don’t provide this motion type. And older machines will not have this feature. A parametric program can create the spiral motion necessary to mill taper threads.

Applications in this category can often keep programs much shorter than CAM system generated programs. The taper thread milling parametric program, for example, is only about fifty lines of G code. Though this is the case, it may actually generate thousands of motions when in use. If generated on a CAM system, these motions would require thousands of lines of G code.

Hopefully this answers your questions. I did get a little wordy, but I didn’t get too specific, so please let me know if you have more questions.
http://www.cncci.com/resources/tips/incr-abs%20and%20parametric.htm

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If your machine does not have a spindle encoder, you should be using a “floating” tapping holder. The holder will extend or compress to make up for mismatches in speed and feed.

The spindle takes longer to reverse directions than the feed. A machine with a spindle encoder will recognize this, and adjust the feed to match (rigid tapping). If you don’t have an encoder on your spindle, a floating tap holder is the way to go. I have heard of and seen people get away without one by running very low spindle speeds. But if you tap many holes at all, the holder is worth the money. If you go with the floater, you can kick your spindle speeds back up to normal. Just remember a couple things:

(1) The spindle is still going to “coast down”, even more so with higher spindle speeds. On most of our machines this translates into about 1 turn for every 100rpm. Program the depth a little short to keep from coasting too deep, especially on blind holes.

(2) Since the holder can extend, it’s possible for the tap to have not made it completely out of the hole before the machine moves to the next location (snap). Use a larger R-plane to help avoid this.

A couple of the controls we own have features to compensate while “flexible” tapping. Fadal can use a P-code to adjust feed on the way out of the hole. P5, for example, reduces the feedrate by 5% on the way out. Incon allows a D-code to dwell (feed) at the bottom to wait for the spindle to catch up. If you have the spindle encoder, nothing beats M29 rigid tapping.

http://www.cncci.com/resources/tips/tension%20tap.htm

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I see a lot of people use trig to calculate a drill tip or to calculate how much deeper to go with the countersink. A quicker way to calculate a 118 degree drill tip is to multiply the dia. by 0.3 i.e.: 0.250 X .3=0.075 The .3 is a standard established by the fact that your answer would be .3 if it were trig’d out for a 1″ dia. Try it! You can do the same for different countersinks, too. Use the value 0..575 (instead of 0.3) for an 82 degree countersink.

http://www.cncci.com/resources/tips/drill%20point.htm

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GREETINGS FROM SOUTH AFRICA! I HAVE RECENTLY STARTED PROGRAMMING IN MACRO B AND HAVE WRITTEN THIS PROGRAM TO CUT PILLAR HOLES, ETC IN MOULD PLATES. THIS PROGRAM CUTS A HOLE OF ANY DIAMETER AT ANY POSITION WITH ANY DEPTH OF CUT USING ANY DIAMETER CUTTER. THERE IS NO NEED FOR RADIUS COMPENSATION AS YOU CAN CHANGE THE CUTTER DIAMETER OR THE HOLE DIAMETER TO GET THE SIZE YOU REQUIRE. YOU CAN SET THE DEPTH OF CUT TO MORE THAN THE TOTAL DEPTH OF THE HOLE TO JUST TAKE ONE CUT. THE 180 DEG. LEAD-IN AND LEAD-OUT WITH A RADIUS PLACES LESS STRAIN ON THE CUTTER AS IT COMES INTO CONTACT WITH THE MATERIAL TO BE CUT. HERE IS THE PROGRAM :

* :8000(PILLAR HOLES)
* #100=1.0(CUTTER DIAMETER)
* #101=30.0(X CENTRE)
* #102=30.0(Y CENTRE)
* #103=0.0
* #104=30.0(DEPTH OF HOLE)
* #105=50.0(DIA OF HOLE)
* #106=3000(SPNDLE SPEED)
* #107=500.0(FEED)
* #108=10(TOOL POS)
* #110=20.0(DEPTH OF CUT)
* G00G91G28Z0.0
* G91G28X0.0Y0.0
* T#108M06
* G00G90G54X#101Y#102S#106M03
* G43Z10.0H#108M08
* N1WHILE[-#104LE#103]DO1
* #103=[#103-#110]
* IF[-#104GT#103]GOTO20
* G1Z#103F[#107/3]
* G03X[#101+#105-#100/2]R[[#105-#100]/4]F#107 I-[#105/2-#100/2]J0.0
* X#101R[[#105-#100]/4]
* G00Z10.0
* END1
* N20#103=-#104
* G01Z#103F[#107/3]
* G03X[#101+#105-#100/2]R[[#105-#100]/4]F#107[[#10-#100]/4]
* G00Z10.0 M09
* G00G91G28Z0.0
* G91G28X0.0Y0.0
* M30

http://www.cncci.com/resources/tips/cicle%20mill.htm

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For most of the Fanuc Series Controllers (FS) OT,16/18T,10/11T you can have a condition where upon every time you attempt a Zorn (Zero Return), a Soft Limit Over Travel occurs. This is especially troublesome with the Z axis of vertical machining centers and the X axis of turning centers. These axes tend to drift during the night. When this happens, here’s what you do:

Release NC Soft OT alarm by Jogging away from the limit. Turn the control’s power off. Depress the “P” key and the “CAN” (cancel) key and keep them depressed when you turn the control on (continue holding P and CAN until CRT Display comes on. Release “P” and “Can” keys. Attempt Zero Return again. Pressing P and CAN makes the control ignore the soft limit, and resets at Decel via prox. If the axis over travels again, more than likely you have a bad Zrn Switch. Usually a Proximity Limit Switch. Check the machine maintenance drawing for schematic and DGN associated. Check the DGN I/O bits or ladder while placing a metal object in “Proximity” of the switch face. Note: Even though an indicating led works, it doesn’t always mean the switch is good.

http://www.cncci.com/resources/tips/zero%20return.htm

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I have been programing for about 2 years, and before that I had been a manual machinist for 15 years. I have found that by making a program easy to read and consistent every time you make one makes it easier for operators and new personnel to read. I have seen many old programs made by previous programmers and even I even have to look hard at it to see what’s going on. If you start it the same and don’t try to put everything on one line the operator knows what to look for and doesn’t get confused. For example MO3 on one line, and the rpm on another. They both go together and should be on the same line. Its just like a sentence. Here is an example of how I write a simple program.

* :0005(so and sos part)
* N1T1( 7/16 CENTER DRILL )
* (STATES WHAT IT IS)
* G40G80G90G54(CANCELS CANNED CYCLES,ABSOLUTE,G54OFFSET#)
* M06 (CHANGE THE TOOL)
* M03S1000 (TURN THE SPINDLE ON CW AT 1000 RPM’S)
* M08 (TURN ON THE COOLANT)
* G00X0Y0 (GO TO INITIAL POSITION)
* G43Z1.0H1T2 (READ LENGTH OFFSET FOR TOOL 1,RAPID TO IS 1″,NEXT TOOL IS TOOL 2)
* G73G98Z-.250R.1Q.05F3.0 (WHAT DRILL CYCLE IS THIS,RETRACT TO POINT IS,DEPTH OF CUT,RAPID BACK TO,PECK AMOUNT,FEED RATE)
* G00Z1.0 (THIS IS FORCE OF HABIT TO REMIND ME TO CLEAR ALL OBJECTS BEFORE I GO TO HOME ZERO)
* M98P0002(SUB PROGRAM THAT INCLUDES ALL DATA TO SEND MACHINE HOME IN Z AND I NEVER EVER HAVE TO WRITE IT AGAIN)
* M30 (END OF PROGRAM)

I’m human and I forget things when I go fast, but if I teach what to look for every time, and where it should be, people tend to be able to find it for themselves and see what missing and what shouldn’t be there All it takes is an extra few moments, and if they get an alarm my guys know what to look for and when that happens they figure it out themselves and learn.

http://www.cncci.com/resources/tips/document.htm

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