Achieving Success in CNC Woodworking

Developing a Successful Cutting Direction Strategy

There are a number of factors that can affect the machining practices of wood. One that comes up a lot for certain hardwoods is the cutting direction, specifically in relation to the grain pattern of the wood. Wood is an anisotropic material. This means that different material properties are exhibited in different cutting directions. In terms of lumber, there are different structural grades of wood related to grain orientation. If the average direction of the cellulose fibers are parallel to the sides of the piece of lumber, then the grains are said to be straight. Any deviation from this parallel line and the board is considered to be “cross-grain”. Figure 1 below depicts a mostly straight grain board with arrows indicating the different axes. Each of these axes exhibits different sets of mechanical properties. Because of these differences, one must be conscious of the tool path and minimize the amount of cutting forces placed on the cutter in order to maximize its tool life.

Figure 1: Mostly straight grain board with arrows indicating different axes

Cutting perpendicular to the grain is known as cutting “across the grain”. In Figure 1 above, this would be considered cutting in the radial or tangential direction. Cutting parallel to the grain is known as cutting “along the grain” (longitudinally in terms of Figure 1). The closer you are to cutting at 90° to the grain of the wood in any direction, the larger the cutting force will be. For example, a tool with its center axis parallel to the tangential direction and a tool path along the longitudinal direction would have less wear than a tool with the same center axis but moving in the radial direction. The second type of tool orientation is cutting across more grain boundaries and therefore yields greater cutting forces. However, you must be careful when cutting along the grain as this can cause tear-outs and lead to a poor surface finish.

The Proper Formation of Wood Chips

When cutting wood parallel to the grain, there are three basic types of chips that are formed. When cutting perpendicular to the grain, the chip types generally fall into these same 3 categories, but with much more variability due to the wide range in wood properties with respect to the grain direction.

Type 1 Chips

Type 1 chips are formed when wood splits ahead of the cutting edge through cleavage until failure in bending occurs as a cantilever beam. A large force perpendicular to the shear plane is produced, causing the wood ahead of the cutting edge to split, forming this tiny cantilever beam. When the upward force finally exceeds the strength of this tiny beam, it breaks off.  These types of chips cause comparatively little wear compared to types 2 and 3, as the material is splitting before coming in contact with the pointed edge. End mills with either extremely high rake or very low rake angles often produce type 1 chips. This is especially true when machining against grain slopes that are greater than 25°. Woods with moisture content less than 8%form discontinuous chips and are at a higher risk of tear-out.

Type 2 Chips

Type 2 chips are the most desirable of the three types in terms of surface finish. They are a result of material failure along a diagonal shear plane, extending from the cutting edge to the workpiece surface. Type 2 chips form when there is a proper balance between the properties of the wood, cutting parameters, and cutter geometry. Woods with a moisture content between 8% and 20%have a much higher chance of forming continuous type 2 chips while leaving a good surface finish.

Type 3 Chips

The last type of chip forms when the rake angle of a cutter is much too low. In this scenario, the cutting force is almost parallel to the direction of travel. This causes a soft material, such as wood, to be crushed rather than sheared away, leaving a poor surface finish. Generally, the surface left behind looks like tiny bundles of wood elements, a surface defect commonly known as “fuzzy grain.” This type of chip occurs more frequently in softwoods as the crushing situation is compounded in low-density woods.

Figure 2: Different types of wooden chips

Extending Tool Life When Machining Wood

Speeds & Feeds Rules of Thumb

There are several different categories of tool wear that occur when machining wood. General rules of machining still apply as RPM has the greatest influence on wear rate. Over-feeding can increase tool wear exponentially and also cause tool breakage. As with most machining operations, a balance between these two is essential. If you are looking to increase your productivity by increasing your speed, you must increase your feed proportionally in order to maintain a balance that keeps the tool properly engaged in the material.

Proper Management of Heat

When cutting tools are exposed to high heat, they begin to wear even faster, due to corrosion. The cobalt binder within most carbide tools on the market begins to oxidize and break free of the cutting edge. This sets off a chain reaction, as when the binder is removed, the tungsten carbide breaks away, too. Different species of wood and types of engineered wood have different corrosive behaviors at high temperatures. This is the most consistent type of wear that is observed when machining MDF or particleboard. The wear is due to the chlorine and sulfate salts found in adhesives as this accelerates high-temperature corrosion.  As with aluminum, when the silica content of a wood increases, so too does its corrosiveness.

Generally, increased tool wear is observed in wood with high moisture content. This trait is due to the increased electro-chemical wear caused by the extractives in wood., Moisture content in wood includes substances such as resins, sugars, oils, starches, alkaloids, and tannins in the presence of water. These molecules react with the metallic constitutes of the cutting tool and can dull the cutting edge. Carbide is more resistant to this type of wear compared to high-speed steel.

Best Coatings for Extended Tool Life in Wood

If you want a longer-lasting tool that will maintain its sharp cutting edge (and who doesn’t), you may want to consider an Amorphous Diamond coating. This is an extremely abrasive resistant coating meant for non-ferrous operations in which the temperature of the cutting zone does not exceed 750 °F. This coating type is one of Harvey Tool’s thinnest coatings, therefore minimizing the risk of any edge rounding and maximizing this edge’s durability.

Avoiding Common Wood Machining Mishaps

Tear Out

Tear out, sometimes called chipped grain or splintering, is when a chunk of the wood material being machined tears away from the main workpiece and leaves an unappealing defect where it used to be. This is one of the most common defects when machining wood products. There are many different reasons that tear out occurs. Material characteristics are something to be considered. Tear out is more likely to occur if the grain orientation is less than 20°relative to the tool path, the moisture content of the wood is too low, or the density of the wood is too low. Figure 4 shows the grain orientation angle relative to the tool path. In terms of machining parameters, it can also occur if either the chip load, depth of cut, or rake angle is too high.

Figure 4: Example of grain orientation angle relative to the tool path

Fuzzy Grain Finish

Fuzzy grain looks like small clumps of wood attached to the newly machined face and occurs when the wood fibers are not severed properly. Low rake or dull cutting tools indent fibers until they tear out from their natural pattern inside, causing type 3 chips to form, resulting in a poor finish. This can be exacerbated by a low feed or depth of cut as the tool is not properly engaged and is plowing material rather than shearing it properly. Softer woods with smaller and lesser amounts of grains are more susceptible to this type of defect. Juvenile wood is known to be particularly liable for fuzzy grain because of its high moisture content.

Figure 5: Example of a fuzzy grain finish

Burn Marks

Burn Marks are a defect that is particularly significant in the case of machining wood, as it is not generally a concern when machining other materials. Dwelling in a spot for too long, not engaging enough of the end mill in a cut, or using dull tools creates an excessive amount of heat through friction, which leaves burn marks. Some woods (such as maple or cherry) are more susceptible to burn marks, therefore tool paths for these types should be programmed sensibly. If you are having a lot of trouble with burn marks in a particular operation, you may want to try spraying the end mill with a commercial lubricant or paste wax. Be careful not to use too much as the excess moisture can cause warping. Increasing your tool engagement or decreasing RPM may also combat burn marks.

Figure 6: Example of burn marks

Chip Marks

Chip marks are shallow compressions in the surface of the wood that have been sprayed or pressed into the surface. These defects can swell with an increase in moisture content, worsening the finish even more. This type of blemish is generally caused by poor chip evacuation and can usually be fixed by applying air blast coolant to the cutting region during the operation.

Raised Grain

Raised grain, another common defect of woods, is when one or more portions of the workpiece are slightly lower than the rest. This blemish is particularly a problem when machining softer woods with dull tools as the fibers will tear and deform rather than be cleanly sheared away. This effect is intensified when machining with slow feeds and the wood has a high moisture content. Variations in swelling and shrinking between damaged and undamaged sections of wood exacerbate this flaw. It’s for this reason that raised grain is a common sight on weather-beaten woods. Work holding devices that are set too tight also have a chance of causing raised grain.

Differentiating Harvey Tool Wood Cutting & Plastic Cutting End Mills

Machinists oftentimes use Plastic Cutting End Mills to machine wood, as this tool has very similar internal geometries to that of an End Mill for Wood. Both tools have large flute valleys and sharp cutting edges, advantageous for the machining of both plastic and wood. The main difference between the Harvey Tool plastic cutters and the woodcutters is the wedge angle (a combination of the primary relief and rake angle). The woodcutter line has a lower rake but still has a high relief angle to maintain the sharpness of the cutting edge. The lower rake is designed to not be as “grabby” as the plastic cutters can be when machining in wood. It was meant to shear wood and leave a quality surface finish by not causing tear-out.

Harvey Tool’s offering of End Mills for Wood includes both upcut and downcut options. The upcut option is designed for milling natural and engineered woods, featuring a 2-flute style and a wedge angle engineered for shearing wood fiber materials without causing tear out or leaving a fuzzy grain finish. The downcut offering is optimized for milling natural and engineered woods and helps prevent lifting on vacuum tables.

For more help on achieving a successful machining operation, or more information on Harvey Tool’s offering of End Mills for Wood, please contact Harvey Tool’s team of engineers at 800-645-5609.

Harvey Performance Company Opens New 79,000-Square-Foot Manufacturing Plant in Gorham

GORHAM, ME (October 13, 2020) – Harvey Performance Company, the parent company of the Harvey Tool, Helical Solutions, and Micro 100 industrial cutting tool brands, last month opened the doors to a new, 79,000-square-foot, state-of-the-art manufacturing facility in Gorham, Maine, to support the tremendous growth and product demand its brands continue to experience.

Harvey Performance Company was quickly outgrowing its Sanford Drive facility in Gorham, Maine, where Helical Solutions products have been manufactured for more than 15 years. The new manufacturing facility, which is just 5 minutes away on Raceway Drive, will become home to Helical Solutions product manufacturing and will serve as an innovation hub for all Harvey Performance Company brands.

“We couldn’t be more excited about this new facility,” said Harvey Performance Company Senior Vice President of Sales Jerry Gleisner. “We’re quite literally opening the doors to countless opportunities for us to serve our customers in ways unmatched in the industry.”

“This new facility is an exciting step for our business, as this investment will create opportunities for us to continue to grow,” said Harvey Performance Company Vice President of Operations Steve Vatcher. “In light of the COVID-19 Pandemic, we worked closely with state and local officials to ensure that the completion of our new facility was done in a way that prioritized the health and safety of all involved. I couldn’t be more proud of how everyone came together to make this facility a reality during these unprecedented times.

“When it is safe to do so, we look forward to hosting the Gorham community, our neighbors for more than 15 years, at our new home for a ribbon cutting ceremony to share this exciting milestone with us.”

Harvey Performance Company’s New Manufacturing Plant Will:

  • Expand upon its current research and development capabilities to design, test, and manufacture innovative and high performing cutting tools.
  • Accelerate Harvey Performance Company’s new product growth while maintaining its in-stock status and same-day shipping options for all catalog standard items.
  • Host its distributor partners and customers in a state-of-the-art setting that showcases its capabilities.
  • Meet the needs of the market by scaling the size of Harvey Performance Company’s business in the future, through added machines and personnel.
  • Attract, recruit, and retain high-quality employees, engineers, and operators with a high-class work environment.

Understanding Wood Properties for CNC Woodworking Projects

Machinists oftentimes confuse wood for being an “easy to machine material” because of how much softer the material is than metal. In some sense this is true, as you can program wood cutting parameters with much higher feed rates compared to that of most metals. On the other hand, however, wood has many unique properties that need to be accounted for in order to optimize the cutting process for maximum efficiency.

Types of Wood

There are 3 main categories of wood: hardwood, softwood and engineered wood.

Hardwood

The textbook definition of a hardwood tree is an angiosperm, more commonly referred to as a broadleaf tree. A few examples would be oak, birch, and maple trees. These types of trees are often used for making high quality furniture, decks, flooring, and construction components.

Softwood

A softwood is a coniferous tree, sometimes known as a gymnosperm. These are typically less dense than hardwoods and are therefore associated with being easier to machine. Do not let the name fool you: some soft woods are harder than some hardwoods. Harvey Tool’s Speeds and Feeds Charts for its offering of Material Specific End Mills for Wood are categorized by Janka hardness for this exact reason. Janka hardness is a modified hardness scale with a test specifically designed for classifying types of wood.

Softwood is used to make furniture, but can also be used for doors, window panes, and paper products. A couple of examples are pine and cedar trees. Table 1 lists 20 common woods with their Janka hardness.

Common Name:Janka Imperial Hardness:
Balsa90
Buckeye, Yellow350
Willow, Black360
Pine, Sugar380
Cottonwood, Eastern430
Chesnut, American540
Pine, Red560
Douglas-Fir, Interior North600
Birch, Gray760
Ash, Black850
Cedar, Eastern Red900
Cherry, American Black950
Walnut, Black1010
Beech, American1300
Oak, White1360
Maple, Sugar1450
Apple1730
Cherry, Brazilian2350
Olive2700
Rosewood, Indian3170
Table 1: Janka Hardness of Common Woods

Engineered Woods

Engineered wood, or composite wood, is any type of wood fiber, particle, or strand material held together with an adhesive or binding agent. Although some of these materials are easier to machine than solid woods, the adhesive holding the material together can be extremely abrasive. This can cause premature tool wear and create difficulties when machining. It’s important to note that some types of engineered woods are more difficult to machine than others, specifically those with a higher amount of binding material. These types should be programmed with less aggressive speeds and feeds. For example, medium density fiberboard (MDF) if more difficult to machine than plywood, but much easier to machine than phenolic.

Figure 1: Example of Medium Density Fiberboard

Properties of Wood

Grain Size

Technically speaking, wood can be considered a natural composite material as it consists of strong and flexible cellulose fibers held together by a stiffer glue-like matrix composed of lignin and hemicellulose. If you think in terms of construction, the cellulose fibers would be the steel rebar, and the concrete would be the lignin and hemicellulose. Wood with large cellulose fibers are considered to be coarse-grained (oak and ash). Woods that have smaller and fewer fibers are considered fine-grained (pine and maple). Softwoods tend to be fine-grained and are therefore stereotyped as being easier to machine since they do not have as many strong fibers to shear. It’s important to note that not all hardwood trees are coarse grained and not all softwood trees are fine-grained.

Figure 2: Simplified diagram of fibers that constitute natural wood. The cellulose fibers run vertically in this depiction.

Moisture Content (MC)

Moisture content (MC) is one of the most important variables to consider when machining wood. An extremely common problem with building anything with wood is its tendency to warp. Moisture variability in the air inevitably affects the moisture content within the wood. Any change in moisture content (whether an increase or a decrease) will disturb the shape of the workpiece. This is why one must take into account what type of moisture a product will be exposed to in its final resting place.

Equilibrium Moisture Content (EMC)

Equilibrium moisture content (EMC) occurs when wood has reached a balance point in its moisture content. Interior EMC values across the United States average at about 8%, with exterior values averaging around 12%. These values vary around the country due to the differences in temperature and humidity. For example, the southeastern United States have an average interior EMC of 11% while the southwest averages about 6% (excluding the coastal region). It’s important to consider what region and application the final product is going to encounter so that the wood with the correct moisture content can be selected before machining. Most species of flat-grain wood will change size 1% for every 4% change in MC. The direction of warping depends on the grain orientation.

Figure 4: Average regional indoor EMC

Generally, power requirements for an operation rise with increasing moisture content, mainly because of the surge in density. Density of wood increases with rising MC. The additional power may be necessary to push a heavier chip out of the cutting zone. It’s worth noting that, like synthetic polymers, wood is a viscoelastic material that absorbs energy as it becomes wetter. The proportional limit of its mechanical properties intensifies as MC increases.

When machining some types of wood, cutting region temperature will surge with increasing MC, but in other species it will decline. Be safe and avoid rapid tool wear by decreasing SFM when machining a wood with a moisture content above 10%. Harvey Tool Speeds and Feeds Charts suggest a decrease of 30 per MC percentage point. As always, though, it depends on the type of wood being machined and the type of operation being performed.

Temperature change is not the only reason higher moisture content is associated with rapid tool wear. Moisture within wood isn’t just associated with water, but also with resins, sugars, oils, starches, alkaloids, and tannin present within the water. These substances react particularly well with high speed steel, and to a lesser degree with carbide.

Knots

A knot is a portion of a branch or limb that has become incorporated in the trunk of a tree. The influence of knots on the mechanical properties of wood is due to the interruption of continuity and change in direction of wood fibers associated with it. These properties are lower in this portion of the wood because the fibers around the knot are distorted and lead to stress concentrations. “Checking” (cracking due to shrinking) often occurs around knots during drying. Hardness and strength perpendicular to the grain are exceptions to generally lower mechanical properties. Because of these last two exceptions, machining parameters should be reduced when encountering a knotted portion of the workpiece to avoid shock loading.

Figure 5: Photo of a typical knot

How to Optimize Results While Machining with Miniature End Mills

 The machining industry generally considers miniature end mills to be any end mill with a diameter under 1/8 of an inch. This is also often the point where tolerances must be held to a tighter window. Because the diameter of a tool is directly related to the strength of a tool, miniature end mills are considerably weaker than their larger counterparts, and therefore, lack of strength must be accounted for when machining with them. If you are using these tools in a repetitive application, then optimization of this process is key.

Key Cutting Differences between Conventional and Miniature End Mills

Runout

Runout during an operation has a much greater effect on miniature tools, as even a very small amount can have a large impact on the tool engagement and cutting forces. Runout causes the cutting forces to increase due to the uneven engagement of the flutes, prompting some flutes to wear faster than others in conventional tools, and breakage in miniature tools. Tool vibration also impacts the tool life, as the intermittent impacts can cause the tool to chip or, in the case of miniature tools, break. It is extremely important to check the runout of a setup before starting an operation. The example below demonstrates how much of a difference .001” of runout is between a .500” diameter tool and a .031” diameter tool.

The runout of an operation should not exceed 2% of the tool diameter. Excess runout will lead to a poor surface finish.

Chip Thickness

The ratio between the chip thickness and the edge radius (the edge prep) is much smaller for miniature tools. This phenomena is sometimes called “the size effect” and often leads to an error in the prediction of cutting forces. When the chip thickness-to-edge radius ratio is smaller, the cutter will be more or less ploughing the material rather than shearing it. This ploughing effect is essentially due to the negative rake angle created by the edge radius when cutting a chip with a small thickness.

If this thickness is less than a certain value (this value depends of the tool being used), the material will squeeze underneath the tool. Once the tool passes and there is no chip formation, part of the plowed material recovers elastically. This elastic recovery causes there to be higher cutting forces and friction due to the increased contact area between the tool and the workpiece. These two factors ultimately lead to a greater amount of tool wear and surface roughness.

Figure 1: (A) Miniature tool operation where the edge radius is greater than the chip thickness (B) Conventional operation where the edge radius is small than the chip thickness

Tool Deflection

Tool deflection has a much greater impact on the formation of chips and accuracy of the operation in miniature operations, when compared to conventional operations. Cutting forces concentrated on the side of the tool cause it to bend in the direction opposite the feed. The magnitude of this deflection depends upon the rigidity of the tool and its distance extended from the spindle. Small diameter tools are inherently less stiff compared to larger diameter tools because they have much less material holding them in place during the operation. In theory, doubling the length sticking out of the holder will result in 8 times more deflection. Doubling the diameter of an end mill it will result in 16 times less deflection. If a miniature cutting tool breaks on the first pass, it is most likely due to the deflection force overcoming the strength of the carbide. Here are some ways you can minimize tool deflection.

Workpiece Homogeny

Workpiece homogeny becomes a questionable factor with decreasing tool diameter. This means that a material may not have uniform properties at an exceptionally small scale due to a number of factors, such as container surfaces, insoluble impurities, grain boundaries, and dislocations. This assumption is generally saved for tools that have a cutter diameter below .020”, as the cutting system needs to be extremely small in order for the homogeny of the microstructure of the material to be called into question.

Surface Finish

Micromachining may result in an increased amount of burrs and surface roughness when compared to conventional machining. In milling, burring increases as feed increases, and decreases as speed increases. During a machining operation, chips are created by the compression and shearing of the workpiece material along the primary shear zone. This shear zone can be seen in Figure 2 below. As stated before, the chip thickness-to-edge radius ratio is much higher in miniature applications. Therefore, plastic and elastic deformation zones are created during cutting and are located adjacent to the primary shear zone (Figure 2a). Consequently, when the cutting edge is close to the border of the workpiece, the elastic zone also reaches this border (Figure 2b). Plastic deformation spreads into this area as the cutting edge advances, and more plastic deformation forms at the border due to the connecting elastic deformation zones (Figure 2c). A permanent burr begins to form when the plastic deformation zones connect (Figure 2d) and are expanded once a chip cracks along the slip line (Figure 2e). When the chips finally break off from the edge of the workpiece, a burr is left behind (Figure 2f).

Tool Path Best Practices for Miniature End Mills

Because of the fragility of miniature tools, the tool path must be programmed in such a way as to avoid a sudden amount of cutting force, as well as permit the distribution of cutting forces along multiple axes. For these reasons, the following practices should be considered when writing a program for a miniature tool path:

Ramping Into a Part

Circular ramping is the best practice for moving down axially into a part, as it evenly distributes cutting forces along the x, y, and z planes. If you have to move into a part radially at a certain depth of cut, consider an arching tool path as this gradually loads cutting forces onto the tool instead of all at once.

Machining in Circular Paths

You should not use the same speeds and feed for a circular path as you would for a linear path. This is because of an effect called compounded angular velocity. Each tooth on a cutting tool has its own angular velocity when it is active in the spindle. When a circular tool path is used, another angular velocity component is added to the system and, therefore, the teeth on the outer portion of tool path are traveling at a substantially different speed than expected. The feed of the tool must be adjusted depending on whether it is an internal or external circular operation. To find out how to adjust your feed, check out this article on running in circles.

Slotting with a Miniature Tool

Do not approach a miniature slot the same way as you would a larger slot. With a miniature slot, you want as many flutes on the tool as possible, as this increases the rigidity of the tool through a larger core. This decreases the possibility of the tool breaking due to deflection. Because there is less room for chips to evacuate with a higher number of flutes, the axial engagement must be decreased. With larger diameter tools you may be stepping down 50% – 100% of the tool diameter. But when using miniatures with a higher flute count, only step down between 5% – 15%, depending on the size of the diameter and risk of deflection. The feed rate should be increased to compensate for the decreased axial engagement. The feed can be increased even high when using a ball nose end mill as chip thinning occurs at these light depths of cut and begins to act like a high feed mill.

Slowing Down Your Feed Around Corners

Corners of a part create an additional amount of cutting forces as more of the tool becomes engaged with the part. For this reason it is beneficial to slow down your feed when machining around corners to gradually introduce the tool to these forces.

Climb Milling vs. Conventional Milling

This is somewhat of a tricky question to answer when it comes to micromachining. Climb milling should be utilized whenever a quality surface finish is called for on the part print. This type of tool path ultimately leads to more predictable/lower cutting forces and therefore higher quality surface finish. In climb milling, the cutter engages the maximum chip thickness at the beginning of the cut, giving it a tendency to push away from the workpiece. This can potentially cause chatter issues if the setup does not have enough rigidity.  In conventional milling, as the cutter rotates back into the cut it pulls itself into the material and increases cutting forces. Conventional milling should be utilized for parts with long thin walls as well as delicate operations.

Combined Roughing and Finishing Operations

These operations should be considered when micromachining tall thin walled parts as in some cases there is not sufficient support for the part for a finishing pass.

Helpful Tips for Achieving Successful Micromachining Operations

Try to minimize runout and deflection as much as possible.This can be achieved by using a shrink-fit or press-fit tool holder. Maximize the amount of shank contact with the collet while minimizing the amount of stick-out during an operation. Double check your print and make sure that you have the largest possible end mill because bigger tools mean less deflection.

  • Choose an appropriate depth of cut so that the chip thickness to edge radius ratio is not too small as this will cause a ploughing effect.
  • If possible, test the hardness of the workpiece before machining to confirm the mechanical properties of the material advertised by the vender. This gives the operator an idea of the quality of the material.
  • Use a coated tool if possible when working in ferrous materials due to the excess amount of heat that is generated when machining these types of metals. Tool coatings can increase tool life between 30%-200% and allows for higher speeds, which is key in micro-machining.
  • Consider using a support material to control the advent of burrs during a micro milling application. The support material is deposited on the workpiece surface to provide auxiliary support force as well as increase the stiffness of the original edge of the workpiece. During the operation, the support material burrs and is plastically deformed rather than the workpiece.
  • Use flood coolant to lower cutting forces and a greater surface finish.
  • Scrutinize the tool path that is to be applied as a few adjustments can go a long way in extending the life of a miniature tool.
  • Double-check tool geometry to make sure it is appropriate for the material you are machining. When available, use variable pitch and variable helix tools as this will reduce harmonics at the exceptionally high RPMs that miniature tools are typically run at.
Figure 3: Variable pitch tool (yellow) vs. a non-variable pitch tool (black)

Titanium Machining Cost Savings with Helical Solutions

When the manufacturing team at Geospace Technologies was looking for better tool life and improved performance on a Titanium CNC milling job, they turned to Harvey Performance Company and local Application Engineer Mike Kanigowski to dial in some Helical Solutions End Mills. With Mike’s help, Geospace Technologies, led by Lead Mill Programmer Tranquilino Sosa, achieved massive success and cost-savings, which led them to completely shift their tooling repertoire to Helical’s high-performance end mills in their shop.

Struggling with Tool Life

Prior to switching to Helical, Geospace Technologies was experiencing trouble with tool life on a job that required both roughing and finishing toolpaths on a Titanium (Ti-6AL-4V) part. For their roughing pass, Geospace was using a competitor’s 4 flute, 3/8” diameter end mill with a 30° helix angle and TiALN coating. In traditional roughing toolpaths, this tool was running at 1,750 RPM with a 10 IPM feed rate. The tool would take four step downs, three with an axial depth of cut of .200”, and a final pass at .100” for a total depth of .700”.

When finishing, the team used a 1/2” version of the same competitor tool, running at 900 RPM with an 8 IPM feed rate. This would take two passes, one at .400” deep and the last down to the bottom of the part at .700”.

geospace technologies

With this strategy and tooling, the team was creating high-quality parts at a cycle time of 15 minutes and 22 seconds per part, but were only seeing the roughing tool last for 60 parts on average, and the finishing tool for around 120 parts. This was causing tool costs to be higher than they would like, and costing the team precious time with frequent tool changes.

Sosa had seen some of the success that other shops were having with Titanium milling using Helical Solutions end mills, and so they reached out to Kanigowski to see how Helical could help them lower their cost per part while achieving an even better finish.

Dialing in Tool Selection

When Mike got in touch with the team at Geospace, he knew there were some immediate benefits to changing the toolpaths used in this job. Using their ESPRIT software, the team was able to dial in a new program using high efficiency milling (HEM) toolpaths through ESPRIT’s “Profit Milling” technology.

With HEM toolpaths in place, Geospace was going to need new high performance tools to take full advantage of the programming adjustments. After much testing and evaluating several options from Helical’s extensive line of end mills for Titanium, Geospace settled on two solid tools.

Helical offers many different options for Titanium milling in HEM toolpaths. During testing, the team at Geospace decided on Helical EDP 59424, a 3/8” diameter, 7 flute, corner radius end mill. This tool features variable pitch geometry and offset chipbreakers for optimal chip evacuation, reduced harmonics, and minimized tool pressure, as well as Helical’s Aplus coating for high temperature resistance, decreased wear, and improved tool life.

7 flute chipbreaker
7 Flute Chipbeaker Tools Fresh Off the Grinder

When looking at the finishing toolpath, Geospace decided on Helical EDP 82566, a 3/8”, 6 flute, square end mill from Helical’s well known HEV-6 product line. This tool featured a variable pitch design to help mitigate chatter and leave a superior finish. While Helical also offers several tools for finishing toolpaths in Titanium, during testing this tool provided Geospace with the best finish for their specific part geometry.

HEV-6
Example of a Tool from Helical Solutions HEV-6 Tooling Line

Experiencing the “Helical Difference”

With the new tools in place, Sosa’s team reached out to Helical for help dialing in speeds and feeds. The Helical tech team was able to get them set up on Machining Advisor Pro, an advanced speeds and feeds calculator developed by the experts behind Helical Solutions tooling. With this “miracle worker” application in their arsenal, the team was able to easily dial in their new tools for their specific material grade, depth of cut, and machine setup.  

The team saw immediate positive results and cost-savings on this job. They were able to increase their roughing toolpaths to 4,500 RPM and 157 IPM. The finishing path remained largely the same, but resulted in a much improved final part. In total, cycle time dropped from 15 minutes and 22 seconds per part to 12 minutes and 17 seconds per part, which was great, but the improvement in tool life was where Sosa was most impressed.

titanium end mills

With the new Helical end mill in the shop, Geospace was able to run both tools for 580 parts with very minimal wear on the tool. This was a nearly 1000% improvement in tool life for their roughing passes and a 483% improvement in tool life for the finishing operation. In total, one roughing tool was able to last more than 42 hours in the cut before needing to be replaced.

Eliminating the need for a tool change every 60 parts was also a significant time-saver. Constant tool changes were causing serious machine downtime, which was eliminated with the longer tool life experienced with the Helical end mills. What seems like a minor inconvenience will truly add up to dozens of hours in saved time over the course of a few months for Sosa’s team.

titanium machining tool wear
A Closeup of the 7 Flute Chipbreaker After 42 Hours In The Cut

Geospace was thrilled with the results they saw on this Titanium job, as they had never experienced long tool life in Titanium with any other competitor brand. Sosa and his team are excited to continue using Helical Solutions product across all of their other jobs going forward and to continue working with Kanigowski and the Helical tech team on dialing in tool selection and speeds and feeds on future projects.

Please see below for a head-to-head breakdown of the Helical end mills’ performance in terms of total costs and productivity gained versus that of the competitor. These numbers are measured per 1,000 parts, taking into account tooling costs, tool change time, labor costs, running parameters, and cycle times.


titanium machining cost savings

Save Time With Quick Change Tooling

Making a manual tool change on any CNC machine is never a timely or rewarding process. Typically, a tool change in a standard holder can take up to 5 minutes. Add that up a few times, and suddenly you have added significant minutes to your production time.

As CNC machine tool and cutting tool technology has advanced, there are more multi-functional tools available to help you avoid tool changes. However, sometimes it just isn’t feasible, and multiple tool changes are needed. Luckily, Micro 100 has developed a revolutionary new method to speed up tool changes significantly.

What is the Micro-Quik™ Tooling System?

Developed in Micro 100’s world-class grinding facility in Meridian, Idaho, the Micro 100 Micro-Quik™ tooling system is held to the same standards and tight tolerances as all of the Micro 100 carbide tooling.

The quick change tooling system allows for highly repeatable tool changes that save countless hours without sacrificing performance. This system combines a unique tool holder with a unique tool design to deliver highly repeatable and accurate results.

Each quick change tool holder features a locating/locking set screw to secure the tool and a locating pin which helps align the tool for repeatability. Removing a tool is as simple as loosening the set screw and inserting its replacement.

During tool changes, the precision ground bevel on the rear of the tool aligns with a locating pin inside the tool holder. The distance from this locational point to the tip of the tool is highly controlled under tight tolerances, meaning that the Micro-Quik™ tooling system ensures a very high degree of tool length and centerline repeatability. The “L4” dimension on all of our quick change tools, as seen in the image above, remains consistent across the entire product line. Check out the video below for a demonstration of the Micro 100 Micro-Quik™ system in action!

Quick Change Tooling Benefits

The most obvious benefit to using Micro 100’s Micro-Quik™ system is the time savings that come with easier tool changes. By using the quick change holders in combination with quick change tooling, it is easy to reduce tool changes from 5 minutes to under 30 seconds, resulting in a 90% decrease in time spent swapping out tools. This is a significant benefit to the system, but there are benefits once the tool is in the machine as well.

As mentioned above, the distance from the locational point on each tool shank to the tip of the tool is highly controlled, meaning that regardless of which type of tool you insert into the holder, your stick out will remain the same. This allows you to have confidence in the tooling and does not require additional touch offs, which is another major time saver.

By removing additional touch-offs and tool changes from your workflow, you also reduce the chances for human or machine error. Improper touch-offs or tool change errors can cause costly machine crashes and result in serious repairs and downtime. With the Micro 100 Micro-Quik™ system, initial setups become much easier, allowing you to hit the cycle start button with total confidence for each run.

By making a few simple changes to your tool holding configurations and adopting the Micro-Quik™ system, your shop can save thousands in time saved, with less machine downtime and increased part production. To learn more about the Micro 100 Micro-Quik™ cutting tools and tool holders, please visit (URL here to quick change page).