by Bernard Martin

Workholding Solutions
Recently, Jack Burley, the President and COO of BIG DAISHOWA, discussed innovative workholding solutions that are effective in combating vibration, with particular emphasis on the ROC® mineral cast solutions. These advanced solutions play a crucial role in increasing capacity and throughput by reducing burden and transport weights.

Much like a skyscraper, ROC® constructs a steel substructure for stability, precision machined and filled with ground positioning components and fasteners. The assembly is then encapsulated with a composite structure of mineral particles and epoxy resin, creating a working platform that is lightweight, yet stable and superbly dampened.

Mineral particles constitute about 90% of the added weight in these solutions, with the remainder being resin and curing agents. This composition results in an excellent density-to-weight ratio of 2.3 kg/dm^3.

The entire composite structure is produced without the application of heat, which preserves the integrity of the precision machined surfaces and clamping components. Furthermore, the low thermal conductivity and excellent resistance to corrosion of ROC® mineral cast enhance the durability and performance of the workholding solutions.

A key advantage of ROC® mineral cast is its exceptional attenuation rates, which are 6 to 10 times better than those of traditional grey cast iron, thus potentially increasing cell output significantly. ROC® mineral cast components are designed to resist impacts without disturbing the steel positioning and clamping components, due to their low tensile and impact strength.

Customizable to client specifications, ROC® also offers standard columns for horizontal machining center applications with options like integrated Unilock zero-point chucks or grid patterns.

Burley highlighted the ergonomic benefits and how ROC® mineral cast solutions facilitate machine capacity management in manufacturing settings.

Many of these solutions are about 50% lighter than their alternatives, making them highly advantageous for companies looking to standardize operator interfaces and streamline production processes.

By adopting ROC® mineral cast workholding solutions, manufacturers can significantly enhance their machining quality and operational efficiency.

edited by Bernard Martin

Anyone who has ever machined the superalloy titanium knows that it can be a real diva, requiring special care and attention. Chips that won’t break, heat that won’t dissipate, and built-up edges are some of the common ways in which titanium puts up a fight during machining.

However, titanium’s remarkable properties make it a favorite in aviation, motorsport, and medical technology, so it is worth learning how to machine it properly. You never know when a renowned sports car manufacturer will need to place an order for titanium screws.

Whether or not the chemist Martin Heinrich Klapproth named the titanium element after the deities from Greek mythology because of its god-like properties is unclear. But the fact is that its properties make it a superalloy. Extremely tension-proof, very light, and outstandingly resistant to corrosion, titanium offers something other materials and alloys don’t.

Titanium is antimagnetic, biocompatible, and resistant to even the most aggressive media. This expensive material is becoming popular in more fields and applications. It’s no secret to the engineers at Bugatti, who use many titanium parts in their work.

Machining titanium is an investment, as it costs about three to five times more than tool steel. So logically, you want to avoid waste. The careful selection of a suitable cutting tool is only the first step. Manufacturing precision turned parts made of titanium, which are frequently needed in aviation and spaceflight, the chemical industry, vehicle construction, and medical technology, requires tools that are suited to machining this particular material, allowing for the most stubborn titanium alloys to be machined as needed.

But this diva of the materials world can do a number on your cutting tools due to:

• High heat resistance (see diagram)
• Chips not breaking
• Titanium’s distinct tendency to stick to cutting tools
• A low elastic modulus
  (Ti6Al4V = 110 kN/mm2, steel Ck45 = 210 kN/mm2)

Let’s instead take a look at the manufacture of a threaded and grooved shaft made of the standard titanium alloy Ti6Al4V Grade 5/23, as is frequently used in medical technology. With a tensile strength of Rm = 990 N/mm2, yield strength of Re = 880 N/mm2, a hardness of between 330 and 380 on the Vickers hardness scale, and elongation at fracture A5d of approximately 18%, this titanium alloy is typically used for medical implants as well as aviation applications (3.7164) and industrial applications (3.7165). With six percent aluminum and four percent vanadium, and extra-low interstitial elements (ELIs), this alloy is highly biocompatible, inducing virtually no known allergic reactions.

This requires a high-quality surface finish, reliable process safety, and controlled chip removal, all while keeping process times short despite potentially high rates of chip removal. You might assume that most of the heat generated in the turning process is evacuated via the chips, but this isn’t so. Since titanium is a poor thermal conductor, the heat cannot be alleviated from the cutting zone via the chips.

And at temperatures of 1200°C and higher in the cutting zone, the cutting tool can quickly sustain heat-related damage. The easiest things you can do to prevent too much heat from building up are to feed coolant directly to the cutting zone, reduce the cutting force by using a sharp cutting edge, and adjust the cutting speed to suit the process at hand.

Real improvements are made by selecting the correct cutting tool. Since the heat must be evacuated via the cutting edge and the coolant, not via the chips, as is the case with steel, a small portion of the cutting edge must withstand extremely high thermal and mechanical stress. The cutting pressure is reduced by using ground, high-positive indexable inserts with polished flutes, if necessary, with the appropriate coating, minimizing friction in the chip removal process.

These three parameters help prevent heat from being produced in machining. If only a little bit of the heat is reduced further through optimal coolant flow, the cutting edge will have a longer service life. Or the cutting speed (Vc) can be increased again to improve productivity.

So far, so good. But since this diva’s chips don’t like to break, you may face other difficulties. An endless chip could wind itself around the workpiece, your tool, or the machine chuck and pose a hazard to the machine or your safety. It could help to change the direction of rotation and turn the cutting edge around if the machine’s design allows it. If the cutting edge is pointing downward, chips will fall freely to the ground and no longer pose a danger.

However, when working with demanding roughing applications and less-than-stable machinery, you will have to check whether the cutting action allows the chips to be directed towards the machine bed. Once the chips have left the work zone, they can no longer disrupt the process.

If you want to make sure that you choose the right tool for titanium machining, turn to a manufacturer. Some go above and beyond, offering advice based on specific application experience in addition to supplying the cutting tool itself.

ARNO USA is a tool manufacturer that has been around since 1941. In addition to manufacturing one of the largest selections of high-positive indexable inserts, it employs many experienced application consultants who would be happy to share their knowledge to ensure that customers’ manufacturing processes run smoothly.

Its high-positive indexable inserts are sharp enough to keep cutting force to a minimum, and their optional rounded edges ensure excellent stability. Expedient high-tech coatings make them well-equipped against the poor thermal conductivity of this tricky material.

Negative indexable inserts with EX, NFT, NMT, and NMT1 geometries provide an affordable, reliable solution for more basic machining and roughing.

Arno’s positive indexable inserts with geometries PSF and PMT1 are ideal for machining superalloys.

All of these inserts are highly resistant to notch wear and heat when machining tough material. Unique geometries ensure exceptional chip control and process safety. Dedicated titanium machining experts and ARNO customers are well prepared.

For all BIG KAISER fine boring heads type AW, EW, EWN, EWD, EWE, EWB and EWB-UP, the frequency for lubrication depends on use.

If used daily, the recommendation is to oil the boring head every two to three months.

​The best procedure is to range the cartridge to the maximum diameter. Using a lubrication gun, pump oil in the unit until it stops accepting oil and then range cartridge to minimum setting. Excess oil will come out around the dial face (this is normal). If oil is excessively dirty, repeat the process.  

Recommended oils are Mobil Vactra No. 2, BP Energol HLP-D32, Kluber Isoflex PDP 94, or a similar light machine oil. 

by ‍‍Olavi Meriläinen, Jergens guest blog

In the late 1970’s, Finnish inventor and entrepreneur Mr. Olli Kytölä developed a new clamping method for workholding. The simplicity of the idea is mind-blowing even today: instead of moving large machine vise jaws against each other, a small wedge-operated jaw is pressing the workpiece against fixed stoppers. The clamp has two jaws, so possibility to clamp one or two workpieces with one clamp is built-in.

During last 40 years, this wedge operated workholding clamp has become famous with the name OK-VISE Low-Profile Clamp. The core application has always been in CNC milling, an in early days do-it-yourself people used to build their own workholding fixtures using OK-VISE clamps and milling the remaining parts of the milling fixture themselves. ​

When we are talking about clamping the workpiece securely and safely for machining, it is important to look at various clamp models and their strengths.

The features of the machining process and the workpiece typically determine the requirements for the clamp. In most fixtures, so called force-closure is being used.

This means that typically 3 sides of the workpiece have free access to milling tool, and holding force opposing the machining forces is created by friction.
​
When dealing with high forces during machining in force-closure fixtures more friction is needed between the jaw and the workpiece. This can be achieved by selecting a larger clamp, for bigger forces, or a model with enhanced grip for better friction compared to a smooth-jaw clamp.
Luckily, you can find a range of clamp options from us to securely attach even the most challenging workpieces.

In mostly used the jaw slides along the fixture base. These are called hold-down models, because the wedge design holds the jaw down and prevents the jaw from lifting up while clamping.

One way to build a workholding fixture is form-closure, where the geometry of the layout prevents the workpieces from moving.
​
Another and more typical application is force-closure, where the friction between the workholding clamp and stopper jaws create a holding force that prevents the workpieces from moving. In most typical application there are 2 workholding clamps and 2 stoppers, each with the same force clamping the workpiece. When this force is multiplied by friction coefficiency µ, then we can calculate the holding force, in the abovementioned example.

H = 4 µ F
 where F is the clamping force, and friction coefficient varies. Example values when workpiece from steel is in use.
 µ = 0,15            smooth jaws
 µ = 0,28            tungsten carbide coated jaws
 µ = 0,8              serrated jaws

All in all, using a wedge operated clamp is one of the easiest and best ways to build workholding fixtures. Its operation allows you to use it for clamping multiple workpieces simultaneously or when you need a high clamping force in limited space. For more details about our low-profile clamp, we have gathered product information in our instructions.
​
Stay tuned for more updates from OK-VISE as the company continues to innovate and deliver cutting-edge solutions to its customers.

by Bernard Martin

Here are some basic rules of thumb on end mill selection

Navigating the vast array of end mills available in the market can be a daunting task, especially when precision is paramount. To aid in this process, we've outlined a step-by-step guide that addresses crucial considerations for selecting the optimal end mill for your machining needs.

Step 1 – Material Identification: Identify the exact material, its condition (billet, forging, etc.), and hardness (HRC). This information directs you to the Non-Ferrous or Ferrous section of our catalog.

Step 2 – Operation Type: Determine whether you'll be roughing, finishing, or both. This guides the choice of the number of flutes and the need for chip breakers.

Step 3 – Programming Style: Choose between traditional programming, high efficiency programming (HEM), or a combination. This decision influences the number of flutes (Step 8).

Step 4 – ADOC (Axial Depth of Cut): Determine the maximum axial depth of cut the tool will experience in the part. This information helps decide the length of cut (LOC) to deploy.

Step 5 – Reach Consideration: Evaluate obstacles to clear and depths to reach. If necessary, consider a reduced necked tool to maintain length of cut while reaching deeper positions.

Step 6 – Tool Diameter Selection: Consider the machine taper, cut depth, reach, and part geometry. Keeping the tool diameter under 3/4" for 40-taper machines and adapting the diameter to programming style, cut depth, and reach requirements.  Keep in mind  what programming style (Step 3) you’re using as HEM can employ smaller diameters than you may be used to. Decide on your cut depth (Step 4). For traditional programming keep it <2xDia., for HEM keep it below 4xDia.  Decide on your total reach depth (Step 5). If needing to machine 4xDia. look at a necked tool to maintain strength and minimize deflection.

​Step 7 – Corner Radius: Determine if your part requires a corner radius. Running a corner radius on an end mill can extend its life and is especially beneficial for pre-finishing.

Step 8 – Flute Count: Consider the material and programming type to determine the ideal flute count. Non-Ferrous machining typically requires 2-3 flutes for traditional programming and 3-5 for HEM, while Ferrous machining may need 4-5 for traditional programming and 5-7 for HEM.

Step 9 – Tool Holder Selection: Always opt for the most rigid and accurate tool holder with minimal runout. Keep the Total Indicator Runout (TIR) below 0.0005 at the tip of the tool for optimum tool life and success. Consider the use of a side lock holder for specific applications.

Remember, our team at Next Gen Tooling is always available to assist you in selecting the correct product. By following these guidelines, you'll navigate the selection process with confidence, ensuring precision and efficiency in your machining operations.

Saw Thickness and Keyways:

• Challenge: When the saw thickness is less than 0.125", keyways can create stress risers and cracks.
• Solution: Washers are often used to mitigate stress, but their mounting is critical.

Washer Mounting Issues:

• Problem: Breakage, wobble, and rubbing may result from improper washer mounting.
• Solution: Washers must be clean, flat, and bur-free. Even a speck of dirt can lead to wobbling and oversize cuts.

Scoring Marks and Dirt:

• Issue: If a saw breaks, scoring marks around the hole indicate potential dirt, chips, or grit.
• Solution: Regularly inspect and clean washers, ensuring a smooth and debris-free surface.

Nut Tightness:

• Problem: Circular skid marks indicate an improperly tightened nut.
• Solution: The nut must be wrench-tight to ensure stability and prevent wobbling.

Washer Size and Equal Diameter

• Thin saws, especially, should be supported by large washers.
• Washers must have an equal diameter to prevent flexing and rubbing on one side of the saw.

Proper Nut Tightening:

• Always ensure the nut is tightly secured to prevent circular skid marks and maintain stability.

Saw Blade Teeth Breakage Causes:

• Feed Rate: Avoid excessively high feed rates to prevent stress on the teeth.
• Spindle Bearings: Regularly check and replace worn spindle bearings.
• Drive Belts and Sheaves: Tighten loose drive belts and replace worn sheaves promptly.
• Proper Tightening: Avoid improper tightening, as pauses in rotation during feed advancement can lead to breakage.
• Workpiece Indexing: Do not index the workpiece before the saw has cleared the slot.
• Workholding: Ensure the workpiece is securely held and well-supported.
• Blade Dullness: Regularly replace dull blades, as even the best tools wear out over time.

​7-Flute End Mills

• Advantages: Improved surface finish, particularly in finishing applications.
• Disadvantages: Limited chip clearance.
• Suitability: Specialized for finishing in softer materials (ISO P, M, S, H).

Looking for the perfect 5-Axis Self-Centering vise to the test against a leading competitor's vise. We've rigorously evaluated both vises across four critical performance categories to help you make an informed choice for your workholding solution.

Test Categories: 

• Jaw Lift: We examine the vise's ability to securely grip your workpiece, ensuring it won't budge during the most demanding tasks. 
• Jaw Repeatability: How consistent is the vise in holding and releasing your materials? Precision and reliability are key. 
• Jaw Changeover: Time is money in any shop. Find out which vise allows for swift jaw changes, optimizing your workflow! 
• Jaw Recentering: We test the vise's capability to reposition and recenter your workpiece quickly and accurately, saving you valuable time. 

Discover the results and decide which vise is your ideal companion for all your projects.

At Jergens, we're committed to providing top-quality manufacturing solutions, and we believe in transparency. Our goal is to help you make an informed decision when it comes to your tools, and this video is just one example of that commitment.

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