Now Here! GDP CNC TOOLING GUIDE!

At GDP|GUHDO, we have put our resources together to provide a comprehensive CNC Tooling Guide. This guide is designed to provide the knowledge to support the most efficient use of your CNC tooling.  We want to put the information into your hands any way that you can use it, so we also have a downloadable link to a PDF version of the presentation here.

Below is a directory for both the video presentation and the PDF presentation.

Topic Slide # Time
Introduction to CNC Tooling 1-7  0:00
Tool Holders and Clamping Systems 8-22  3:37
Drill Bits and Adapters 23-26  10:11
Sizing Jointing Rebates, Dado Cuts and Grooving 27-47 11:30
Other Common CNC Tooling 48-53 22:57
Material Specific Tooling 54-63  25:52
Profile and Custom Tooling 64-68 28:54
Saw Blade and Grooving Adapters 69-72  31:33
Other Tool Tips 73-80  32:32

 

Precision CNC Tool Holder Options

HSK Collet Chuck, Collet and Router Bit

HSK Collet Chuck, Collet and Router Bit

Standard HSK collet chucks are currently the most common in use in the woodworking industry. They are relatively inexpensive, and highly flexible due to the wide range of collet sizes that are available and easy to interchange.   While HSK style collet chucks are a good choice for most applications, the multiple parts involved in tool clamping (holder, collet and nut). this style chuck does not provide the tightest possible tolerances or clamping pressure. This is one of the shortcomings that has made thermal heat-shrink tool holders popular. 

Thermal (Heat Shrink) Collet Chuck

Thermal (Heat Shrink) Collet Chuck

Heat-shrink tool chucks have been gaining popularity due to the very tight tolerances (0.003mm / .00012″) and extreme clamping pressures used to hold tools in place.  They are balanced to 30.000 rpm.   These chucks offer a slim, light weight design with very high clamping power and accuracy. This choice of tool holder is ideal for use with insert tooling.  When using solid carbide or PCD (Polycrystalline Diamond) tooling, tool changes must be completed by the use of either an in-house heating element or sent out to an existing tool supplier.  Heat shrink chucks have their specific advantages, but they also have limitations.  Not all  diameters are readily available, the cost is higher than standard collet chucks and the additional cost of a heating element for in-house flexibility, without depending on a third party to remove the tool from the holder, can be considerable.

Hydro Chuck

Hydro Chuck

 Hydraulic tool holders are an often overlooked option to thermal tool holders with the same accuracy and more flexibility.  The hydraulic tool holder works by using fluid to compress an internal membrane within the tool holder. The hydraulic fluid delivers uniform pressure around the membrane allowing it to compress equally around the periphery of the cutting tool (shank) providing an even hold on the tool shank. The hydraulic fluid is activated by the use of a T-handle wrench to turn and activate a pressure screw. To release the pressure and cutting tool from the tool holder, simply turn the pressure screw counterclockwise. In addition to the quick set and release feature, here are a few additional benefits and features:

  •  Precise tool clamping tolerance of 0.00012”
  • Transmission of high torque or clamping pressure
  • Quick tool set up and removal
  • No Heating element or torque wrench required
  • Hydraulic fluid provides vibration absorbing features
  • Flexible with the availability of collet reducers
  • Increased tool performance (finish quality & tool life)

 With clamping tolerances that are comparable to heat shrink tool holders, tool changes are simple and quick. In addition, no heating element is required for tool changes. And, like standard collet tool holders, hydraulic tool holders provide the ability to use different shank tools by the use of high tolerance (collet) reducers.

The ease of use, high clamping tolerances and torque can and will benefit your bottom line by extending tool performance and improving finish output.

For additional information, please contact us!

What is Polycrystalline Diamond (PCD) Tooling?

PCD Saw Blade

PCD Saw Blade

In the right application, using PCD tooling can reduce your tooling cost significantly.  PCD (Polycrystalline Diamond) has been used in the wood/composites industry for over 35 years due to its abrasion resistant properties and hardness.  This synthetic cutting edge material was pioneered by General Electric’s Specialty Materials Division.  PCD is composed of diamond particles that are sintered with a metallic binder at extreme temperatures and pressures,  creating the hardest and one of the most abrasion resistant materials used in cutting tools. Tooling that utilizes this specialized material is now used in a wide range of machining applications including sawing, routing, drilling and profiling to maximize tool life and reduce production cost.  Ideal material applications include cutting chipboard, MDF, particle board, HDF,  and many composite materials including solid surface, fiberglass and phenolic.

PCD tooling

PCD Tooling in HSK 63F Collet Chucks

Like tungsten carbide, PCD is available in multiple quality grades. Most machine applications are supplied with standard quality grades with varying grain size. More demanding applications may be supplied with coarser grain or a “polished” tip.  Polished PCD helps prevent material buildup on the cutting surface (face) which improves tool performance due to less heat generating in the cut.  If you are considering using diamond tooling or if you have any questions concerning the feasibility of using polycrystalline diamond tooling, you can count on GUHDO to provide the guidance and knowledge to solve your most difficult machining applications, click here to contact us now.  In addition to delivery state-of-the-art PCD tools, we also sharpen PCD in-house at our facility in Marietta, GA.

PCD Radius Cutter

PCD Radius Cutter

Tooling Basics for CNC Machining

Below is an article GDP|GUHDO contributed to FDMCdigital.com January 2015 edition (formerly FDM/Cabinetmaker) 
Understanding fundamentals of CNC tooling can make a huge difference in your costs, productivity, and efficiency.  Most CNC machining centers for wood, plastics and composite machining today are equipped with steep taper ISO/SK/BT style, or more frequently HSK style tool holders .  My favorite analogy when discussing tooling basics is the automobile (i.e. the CNC machine), the rims (the tool holders) and the tires (the cutting tool). The most well-designed car won’t go very far if it has bad rims and cheap or faulty tires. Let’s look at the importance of proper cutting tool selection and the outside factors that affect tooling choice as well as other considerations that will directly influence the machining cycle.
CNC Tool Holders - HSK 63F, RDO35 and ISO30

CNC Tool Holders – HSK 63F, RDO35 and ISO30

Start with parameters
Depending on the cutting process that needs to be accomplished, understanding the machine parameters, output, spindle, clamping and tooling options is essential. Material hold-down and dust collection setup will all play a role in the process, as will the quality, density, abrasiveness and surface finish of the material to be machined. Cutting tool selection will be predicated on the basis of understanding the foregoing properties that are already pre-determined, the expectations of anticipated feed speeds to be achieved (capacity) and cost efficiency. These all contribute in making the decision of what tooling is most suitable and cost-effective for the job.
Most CNC machining centers for wood, plastics and composite machining today are equipped with steep taper ISO/SK/BT style, or more frequently HSK style tool holders (Picture 1). The standard HSK tool holders have very high levels of accuracy, with a runout tolerance of 0.003mm (.0001”). A tool holder that is supplied with a ball bearing collet nut, rather than a single piece static nut, is preferred. The ball bearing uncouples the inner ring from the torque/threaded part of the nut (Picture 2) so the circular motion of the nut is completely converted into clamping force without any frictional loss. Advantage: more clamping force, less wear and the tool holder can be used to run both clockwise and counter-clockwise.
The most common versions of tool holders used in wood/plastics/composites utilize ER32, ER40 or RDO35 (SYOZ25) collets and their differences are shown in this chart:
Collet Style Overall Length Clamping Tolerance Max Size Diameter Available
ER32 40mm 1mm 20mm 3/4″
ER40 46mm 1mm 25mm 1″
RDO35/SYOZ25 52mm 0.15mm(premium) or 0.5mm 25mm 1″
HSK63 F tool holders, with any of the above collet types, are interchangeable between machines as long as the same “A” dimension (the dimension from top of the HSK shoulder to the bottom of the collet nut) is the same.
Specialty tool holders
While standard collet chucks are excellent clamping choices for most applications, there are heat shrink and hydro tool holder options for more specialized applications. Heat shrink tool holders are beneficial in high speed machining operations and do not use a collet system as the tool shank is mounted straight into the heat shrink chuck. A heat shrink chuck can only accommodate one size tool shank and generally requires an additional (and sometimes substantial) cost investment for heating equipment to mount and remove the tool from the chuck. It’s a great choice for carbide insert tooling, for instance, where tool and chuck are assembled at the manufacturer and won’t need to be removed for service. See Picture 3.
Another option is the hydro chuck, which also has the advantage of bypassing a collet system reducing compounded tolerances between machine and tool. Hydro chucks are balanced to 25,000 rpm and available in all common metric sizes. (10mm to 25mm). See Picture 4.
Cutting tool options
Moving on to the cutting tool options, it’s important to understand that this is the wrong place to worry about initial tool cost. Accurate cutting tool cost is measured by cost per linear foot machined. Choosing the wrong tool can severely restrict and limit the machine’s capabilities and even give back some of its selling features.
Accuracy, cost-effective production, superior finish quality, waste reduction and maintaining the integrity of machine and spindle all boil down to tool holder and cutting tool selection. Poor quality tool holders or out of balance cutting tools will end up costing far more than might initially meet the eye. Whether the choice is solid carbide spiral tools, insert tools, custom profile tooling or PCD (polycrystalline diamond) tooling, a close look at the pros and cons of each type is something well worth researching and understanding. One company can easily waste thousands of dollars if using ¾” 2-flute solid carbide compression bits to machine table tops, for instance, when a comparable 2-flute carbide insert compression bit will easily out-perform for a small fraction of the cost.
A phenolic fabricator may go through many solid carbide bits every day when a polycrystalline diamond (PCD) bit (special design for phenolic) will run considerably longer and reduce overall machining cost. Someone purchasing a carbide-tipped round-over bit to run on a CNC machine will buy a lot more bits and never maintain uniformity, when an insert tool will maintain constant diameter and hold dimensional accuracy throughout at a lower cost.
Use tools correctly
Whatever tool choice is made, the most important aspect will be using it correctly. The best cutting tool can only perform well if it is used within the parameters it was designed for. The basis of successful cutting tool performance is a synergy of machine quality/integrity, material hold-down, dust extraction, the clamping system (tool holder/collets) and tool and material composition operating under correct machining parameters.
The most important point to consider with any cutting tool is the actual chip load it will generate during the cutting cycle. If the chip load is not within the ideal range for the material being machined, it will result in either overheating of the tool and very short tool life, or, pushing the tool beyond its limits resulting in tool failure (breakage). A very prominent notion is, for instance, that more flutes on a router bit will yield a better finish. This is absolutely not the case. What leads to the best cutting results is the cutting edge moving through the material at the right speed, i.e. chip load. This single factor is probably the most responsible for tool life.
Understanding chip load
So, what is chip load? Simply put, it is the size/thickness of the chip being removed per flute/cutting edge with every revolution of the tool. So, going from a 2-flute bit to a 3-flute bit, the size of the chip is reduced by 33% if the feed rate is not adjusted accordingly. A smaller chip will increase the heat generated during the cut as the chips cannot be extracted out of the cut fast enough and are re-cut into yet smaller particles. Chip load charts found online or provided by tooling manufacturers should all be considered as a starting point/reference range only and it is up to the user to find the ultimate “sweet spot” that provides a combination of the longest tool life, finish and cost efficiency.
The chip load formula is as follows:
                  Chip Load = Feed Rate (inches per minute) / (RPM x number of flutes)
Example:
                   Chip Load = Feed Rate 600”/minute / (18,000×2 flutes) Chip Load = 0.017”
Increasing the chip size per tooth will decrease the quality of the cut, while decreasing the chip size per tooth will shorten the tool life, so it’s important to find the ideal middle where both finish and tool life are optimum.
DSC_0939

3 flute diamond tipped bit for fast feed rates.

Cutting direction
Another consideration is whether to climb cut or conventional cut. With climb cutting, the direction of the feed is identical to the direction of the cutting edge. (As an important side note, this method of cut should never be attempted with a manual fed operation as it can result in very dangerous material kick-back). Climb cutting provides a better finish quality. When conventional cutting, on the other hand, the material is feeding against the direction of the cutting edge which exerts less cutting force on the tool and increases the tool life accordingly.
In summary, cutting tools and clamping systems play a paramount role in a CNC machining center delivering its promise of optimization, capacity, waste reduction and cost savings, as none of these promises can fully materialize without the contributions of high-quality tooling and accessories.
Karin Deutschler, president of GUHDO USA Inc., has been selling diamond tooling since its introduction in the U.S. in 1982. You can contact her and the GDP|GUHDO team at 1-800-544-8436 or www.guhdo.com.
This article appeared in FDMC, January 2015. ©Copyright 2015, All Rights Reserved.