Coatings for Industrial Cutting Tools
Posted on August 28th, 2020 | By WayKen Rapid Manufacturing
If you’ve ever ordered parts from CNC milling services, you may know that custom machining costs a considerable sum of money. Upon looking at the total quote, some of the clients gasp and have a lot of questions regarding the pricing of the milling shops. Well, this article’s aim is to explain what a?CNC tungsten carbide inserts milling job price consists of.
What Is CNC Milling?
CNC milling ( computer numerical control milling ) is a machining process through controlling computers and rotating multipoint cutting tools that can quickly remove the material from the workpiece and create custom-designed parts or products.
Through the CNC milling process, we can machine various materials such as metal, plastic, glass, wood, and produce a variety of custom-designed parts and products.
The?Advantages?of?CNC?Milling
WayKen can offer cost-effective milling solutions whether you need a single part, small batch of prototypes, or full productions.
- Can produce complex parts
- Cost-effective for prototyping
- Short-run production
- High dimensional tolerances
- Smooth finishes
- Various Carbide Inserts materials available
- Low cost
- 100% quality
- Fast delivery
- Excellent After-sales
The Importance of Cost Calculation for Milling Services
First of all, it is important to speak about why an accurate estimate of the machining cost is important. After all, there are a lot of different elements that contribute to the overall cost of a CNC milled part. The importance of consistent quoting by the CNC milling services ensures trust between the client and the manufacturer, makes it possible to understand where the minimum price is (when you don’t get any profit margin but are able to work and pay your employees salary), allows the manufacturer to control the profits and estimate the necessary resources for each job.
Stock Material
Stock material is the most basic cost. You need something to mill from, right? With CNC milling, choosing the right stock is usually easy. You look at the geometry of the final part (mostly, the form and the maximum dimensions), choose a standard stock type (most often a block or a plate for milling operations), and add a couple of centimeters in thickness to the maximum dimensions of the final part. Some milling services make it possible to upload your model of the final part and a milling cost estimation program will find a suitable stock for you.
Tooling
The tooling consists of all the jigs and fixtures, loading mechanisms, tool holders, and of their similar elements that are required to fix the base elements of the milling manufacturing system. These costs are highly individual and cannot be estimated automatically. The good news is that the majority of tooling in CNC milling shops is flexible and will fit 80% of the parts that come through this shop but there are always 20%. Since the cost of tooling is high, it is recommended to change the design of the part a little bit so it can be manufactured without the extra purchases.
Cutting Tools
Cutting tools, as well as cooling liquids, are consumables. Cooling liquid is recycled by the modern milling centers so its cost is negligible. But the percentage of cutting tools in the total of the milling price can be quite costly. Why is that? The answer is simple. This depends on the material. For example, tools for CNC milling acrylic or other soft plastics will be usable for a lot of operations because those materials are soft and do not damage the tool insert. However, harder materials, titanium alloys being on the top of that list, will wear the tools faster.
Apart from that, some CNC operations require specialized tools. For example, diamond machining inserts are much more expensive than carbide ones. CNC milling services usually have a set of recommended tool inserts for each material and will include those in the total.
Machinist Salary
This part of the machining costs is the most understandable. The work is carried out by an employee who has a per hour rate to his CNC services. If your part is large, additional loading and unloading rates may be added to the quote. It should be noted that the machinist is paid for preparation time as well since he sets up the fixtures, tunes up the cutting tools, and so on.
Machine Costs
Machine tools, especially 5-axis CNC milling centers use quite a lot of power and some are mounted with pneumatic systems additionally, which further enhances the use of electricity. Apart from that, companies have to take depreciation costs into account. All of that comprises the rate of a machine tool per hour. Naturally, if the part has to be processed on multiple machine tools (milling and turning both, for instance) then all the rates are added and multiplied by the processing time.
Quality Costs
Different parts have various quality demands. The better the precision and surface finish of the part, the more complex features it has, the more it will cost. So, some CNC shops add a tolerance coefficient when online quoting the jobs. That makes clients more careful when choosing the quality of their parts, saves time, and increases overall business efficiency. In addition, when a batch of parts is ordered, you can insert a percentage of faulty parts. The lower the percentage, the more often the machinist will have to check each corresponding part and the more expensive the whole job will be.
Shipping
We are living in a global world and it is often that a client from Europe orders CNC milling china services. Despite having a lot of different transport companies, shipping still costs money. Usually, machine shop managers let you choose from multiple methods of shipping with different price ranges, you have to include the weight and dimensions of the final part, of course, because shipping a small 0,5 kg shaft is different from shipping a whole set of injection molding dyes. If the shipping is free, then its price is just hidden into the profit margin of the total but the majority of CNC milling shops specify how much you’ll pay for shipping. Some companies can even offer to send your order to a side shipping company that you trust.
Profit Margin
Profit margin is never shown to the client but its coefficients are included in each part of the whole price. If the profit margin is zero (for shops where the business is hard), it means that all the money from the milling goes to cover the expenses and pay the salary. Basically, the business has worked, pays its people, and gets just enough to make ends meet but it doesn’t grow or develop. On the other hand, with a large profit margin, the milling shop gets a lot of extra money for each order but the demand is definitely lower since fewer people are ready to pay more money.
How WayKen Can Help You
CNC mills is a kind of flexible machining method that can manufacture parts in various shapes from soft metals like aluminum, harder metals like steel, and plastics such as acetal.
At Wayken, we can offer fast and cost-effective milling solutions no matter what you need a single part, a small batch of prototypes, or full production order. If you are interested in our CNC milling services, please don’t hesitate to contact us: info@waykenrm.com.
Beginning the AM Journey： An Uphill Battle
Titanium is often characterized as a “challenging workpiece material.” Certainly, machining this material is a challenge to milling machines, cutting tools and workholding accessories that are suitable for machining more common materials such as mild steel, cast iron or aluminum. With appropriate machines, cutters and related equipment, however, machining titanium can be a successful and profitable operation for the knowledgeable and committed machine shop.
The key is understanding the nature of titanium and the somewhat complex interactions among the components of the machining system that titanium calls for. Examining one end mill family specifically designed and engineered for titanium milling brings out many of these interactions. That is, the features and characteristics of these end mills reflect the implications of a complete system optimized for titanium machining.
This representative end mill family is VariMill II ER from Widia (Latrobe, Pennsylvania). It is the five-flute expansion of the original four-flute VariMiIl, hence the II. The five flutes are unequally spaced. ER stands for eccentric relief—the version of this end mill that is best-suited for titanium because the eccentric relief gives the cutting edges extra strength for the high feeds at relatively low rpms that titanium requires. Though primarily designed for roughing and finishing applications in titanium aerospace parts, it can be used for slotting, ramping and plunging of titanium and stainless steel in virtually any industry.
David Buchberger, who represents Widia through Hi-Speed Corp. (Thousand Oaks, California), specializes in advising aerospace shops in titanium cutting. He explains why this cutter work so well in titanium. For example, the correct cutting edge for titanium is important because this material tends to work-harden, he says. Titanium quickly loses what low malleability it has when “beaten” by cutting speeds that are too high. “Titanium likes a big chip to clear material before it hardens. A strong, sharp edge, with the thrust of a rigid, high-torque machine structure to power it, can shear the titanium effectively,” he says. The eccentric relief on the edges of the VariMill II ER creates positive orientation on the radial and axial angles of this edge, which promotes this shearing action.
The underlying foundation for strong, sharp edges, however, has to be a tool with a strong, thick core that makes the entire tool rigid. For this reason, the flutes are more open at the tip of the tool where space for chip evacuation is needed, but as the core runs up to the shank, it becomes heavier to provide integrity to the tool and resistance to deflection, Mr. Buchberger explains.
The flutes are unequally spaced to create a consistently variable impact on the workpiece that breaks up any regular frequency that might match a harmonic in the machine structure to create vibration, detectable as chatter. Of course, other sources of chatter, such as weaknesses in the machine structure or clamping methods, must be addressed in the system.
The coating on the end mill plays a role as well. The VariMill II ER end mills are coated with AlTiN (aluminum titanium nitride), which helps keep the edges sharp by resisting cracking and, more importantly, making surfaces that contact the workpiece smooth and slick so they generate less frictional heat. “Heat buildup accelerates deterioration of the cutting edges, so controlling friction reduces one of the negative factors that shortens tool life,” Mr. Buchberger says.
Because these end mills are designed to be center-cutting, an inspection of the flat end of the tool Tungsten Carbide Inserts shows a strong web across the root. This design eliminates a dead spot in the center that might drag across the floor of a pocket or bottom of a slot. The edges along the tip must also be prepped for sharpness and strength.
As a standard item, the VariMill II ER end mill offers the Haimer SafeLock anti-pullout clamping feature on tools 0.5 inch (12 mm) and larger in diameter. “This system gives the tool more stability and greater concentricity in the holder, in addition to countering pullout forces, so its benefits are multidimensional,” Mr. Buchberger says.
He adds that the primary concern for the programmer is having the correct speeds and feeds. “The concept is to spin the tool slowly and take big bites. A surface speed of 160 to 200 fpm is the best range.” He says this is more important than elaborate toolpath strategies.
Finally, CNMG Insert he stresses that any approach to machining titanium must be a complete system—the right tool, the right machine, the right clamping and so on. “When shops take care to do titanium milling right and invest in the appropriate technology, which includes carefully chosen cutting tools, they will have a system that makes machining titanium no more challenging than other operations,” he says. “The challenge is understanding a systematic approach and implementing it fully in the first place. He also suggests working with a cutting tool supplier who will base tooling recommendations on a review of the entire titanium machining operation. “Any weak link in the process can be disastrous. No cutting tool is the best or right choice if other elements of the system are sub-optimal, he concludes.
The VariMill II ER covers more than 100 standard line items ranging from 3/8 to 1.0 inch (10 to 25 mm) in diameter and is available globally.
Switch from Negative to Positive Tool Offsets
Titanium polishing is an important aspect of titanium part surface finishes that includes several techniques. It majorly removes material from the titanium part’s surface to smoothen it. Polishing the titanium metal part improves intrinsic properties such as biocompatibility, strength, corrosion resistance, wear resistance, and high-temperature resistance.
While advantages, titanium polishing should be a stepwise procedure to avoid mistakes and undesirable results. As a result, this article will introduce titanium polishing so that you can understand how to polish titanium and the application of the process in industries that use titanium material.?
What is Titanium Polishing?
Titanium polishing is a process that uses a buffing wheel and a polish wax to reduce the roughness while increasing the physical appearance of a titanium part’s surface. After machining titanium, polishing occurs to give the titanium part additional protection and a better surface finish (leaving a Ra of 0.1-0.05 micrometer).?
Furthermore, the polishing process gives you a high level of control as it allows polishing small and complex titanium parts with great precision. However, the final color and texture of the final part may vary depending on the condition of the unpolished titanium and the sandpaper grade used.?
How to Polish Titanium with A Mirror Finish?
Just like most surface finishing techniques, polishing a titanium part is an easy process. Follow the steps below on how to go about the process:
Step 1: Degreasing and Cleaning Process
Titanium manufacturing processes can leave dirt and residues of oil and grease on a titanium part. As a result, it is essential to prepare the surface before any finishing process using the sub-steps below:
- Remove oil residues using degreasing agents, e.g., spray rinsing;
- Fill a bowl with enough clean water;
- Submerge the titanium part in clean water;
- Add a small quantity of your preferred cleanser (e.g., mild soap, ammonia, or glass cleanser) ;
- Leave for a few minutes;
- Rinse with warm water and dry with a clean towel.?
Note: Do not use chlorine, bleach, or any other chemical that could affect the properties and aesthetical quality of the titanium part.
Step 2: Sanding process
Use sandpaper to smoothen the surface. The sanding process is similar to the precision grinding process. With sanding, you remove the oxidized layer and a very thin titanium coating. Sanding also improves the adhesion of the metal polish. To do this:
- Apply a lubricant on the titanium part’s surface;
- Place the sandpaper on a hook pad attached to a drill;
You can use different grades of sandpaper. Usually, you start with rough grades and go all the way to smooth grades. For instance, you can start with 200 grit sandpaper, then move to 800 grit sandpaper and go as high as 2000 grit sandpaper, depending on how you want the surface to be.? - After, apply a lubricant on the sandpaper;
- Place it on one edge of the titanium plate and move over horizontally till it gets to the other edge.
Do this till you’ve covered the entire surface of the part. Repeat for the different grades of sandpaper.?
Note: It is important to apply gentle and even pressure to all areas to have even surface patterns during this part of titanium marking.?
Step 3: Buffing Process
The buffing process gives the needed shiny glass-like appearance. To go about this:
- Clean the titanium surface with an alcohol-based cleanser;
- With a metal polish and a buffing wheel, polish the titanium surface. Apply water intermittently to lower the generated heat.
Step 4 Final Finish
Even after buffing, the part may have marks on it. To conceal these marks,?
- Apply a paint polish to a clean towel;
- Rub the part with the clean with even pressure on the surface until it gets visibly darker;
- Spray the surface with water and leave it to dry;
- Apply the sealant on another towel;
- Rub the towel on the titanium surface;
- Leave to dry;
- Wipe with a clean towel to remove excess liquids.?
Different Types of Surface Finish for Titanium Polishing
Based on the polishing force, speed, and the buffing wheel used, there are different surface finishes for titanium polishing in part manufacturing:
Rough Polishing
For rough polishing of titanium parts, use an abrasive buffing wheel made of silicon oxide and titanium polish wax. Here, the polishing force is minimal. Rough polishing is best to round off the corners of the titanium part.?
Medium Polishing
Rough polishing may leave visible lines with a dull surface. Matting abrasive wheels made of aluminum oxide and polish wax can fix this. This increases the surface brightness and smoothness.
Fine Polishing
Fine polishing gives the titanium part a more reflective, i.e., fine surface. To achieve this, use an uncombed soft cotton buffing wheel and a mirror wax polish to exert more pressure on the part surface.
Mirror Polishing
Mirror polished titanium parts have a mirror-like surface finish. You can achieve this using a combed soft buffing wheel made of cotton and polished wax.?Usually, a buffing wheel is ideal as it allows you to polish hard-to-reach places on your part.
The Benefits of Polishing Titanium Parts
To many manufacturers, a good finishing process is as important as the manufacturing process. Titanium finishing offers many advantages, including but not limited to the following.
Improved Aesthetics
The appearance of a product is just as important as its function. Polished titanium has better usability and enhanced functionality. This is because good surface polishing improves the texture of a titanium part, leaving a professional-grade gloss on the surface.?
Stronger Electrical Conductivity
Typically, titanium is a poor conductor of electricity. Electrical conductivity is one of the most important properties of a good metallic part. With good surface polishing, electric current can pass through the titanium part with little resistance. This makes polished titanium useful, especially in the automotive industry.
Optimize Resistance
Corrosion not only renders a part useless, but it may also lead to the ultimate destruction of the metal. Though titanium metal is resistant to solutions of many chemicals, polishing improves its corrosion resistance property.?
Also, a titanium part wears out easily, leading to a gradual deterioration of its surface and function. A well-finished titanium surface reduces the frictional force when it comes in contact with another surface, thereby preventing wear.?
Improved Longevity
A long-life span during usage is one of the many important qualities manufacturers watch out for. Generally, a metal part Coated Inserts with a good surface finish is more durable and will last longer. Polished titanium parts are more resistant to many deteriorating environmental factors. As a result, this guarantees that the finished part will last for many years.
Applications of Polished Titanium Parts
Polished titanium parts are applicable in many manufacturing industries because of the benefits, such as improved longevity, corrosion resistance, etc., they offer.?
Aerospace Industry
The aerospace industry is the major user of polished titanium parts because they are lightweight with outstanding strength and corrosion resistance properties.
The material is applicable in making aircraft engine components due to its excellent heat transmission. Examples of polished Machining Inserts parts include the fan, compressor blades, and many more.
Medical Industry
Manufacturers in the dental and orthopedic field use polished titanium in making parts such as dental implants, hips, and knees. Titanium is highly important here due to its high resistance to the effects of chemicals from food. Also, they have high flexural strength, which reduces the dental implant’s breaking during strong impact.?
Furthermore, when comparing titanium to aluminum and other metals, titanium is highly biocompatible. The human body does not reject them, nor do they trigger an immune response. So, medics use them as artificial joints for the hips, knees, and other joints.?
Automotive Industry
Polished titanium has a high strength-to-weight ratio. Its light weight helps to improve fuel efficiency and lower the operating cost of a vehicle.
Manufacturers in the automotive industry mainly use titanium parts to make a car’s exhaust system. This is because it is a good conductor of heat, which reduces the risk of overheating. Also, its rust and corrosion resistance properties increase the lifespan of the exhaust system.
Additionally, manufacturers use them to make valves, brake calipers, electric vehicle batteries, and some other mechanical parts.?
Marine Engineering
Titanium is the first choice for marine applications as the different types of titanium alloys are all marine grades. These grades are strong and highly resistant to corrosion, especially in seawater.
They are also applicable in seawater desalination as they can withstand the harsh effect of chlorine. Consequently, they replaced the conventional copper alloy pipes in this process. Titanium parts are the buildup components of several pieces of deep-sea equipment.?
Jewelry Industry
Polished titanium parts have a unique mirror finish. As a result, they are popular jewelry materials. Additionally, its lightweight and non-toxicity have contributed to its use in rings, wristwatches, etc. Furthermore, they are good on sensitive skin and do not easily undergo wear, even with incessant use.?
Other Titanium Finishing Options?
In addition to titanium polishing, manufacturers use the processes below to give the part the needed surface finish.
Anodizing
Anodizing is an electrochemical process involving submerging the titanium into an electrolyte solution. Afterward, the operator passes an electric current into the solution.
This converts the surface layer of the titanium part to titanium oxide. Furthermore, the process thickens the natural oxide layer leaving it highly corrosion-resistant and durable.
Note: the anodizing process may affect the thermal conductivity properties of the titanium part.?
Electroplating
Electroplating involves coating the surface of the titanium part with other metals, such as nickel. This improves the surface qualities and enhances the wear and corrosion resistance properties. However, this is time-consuming, and the waste generated may risk an individual’s health and the environment.?
Brushing
This involves using different abrasive brushes to remove flaws and finish uneven titanium surfaces. The brushing process leaves an opaque surface that may not be as bright as a glass-like surface. Though brushing enhances the appearance of a part, it may alter its corrosion resistance properties. Its high cost of operation is another downside.?
Powder Coating
This involves the application of plastics in dry powder form on the surface of the titanium. Powder coating gives a stronger surface finish compared to the traditional painting process. A major advantage is that this coating does not fade easily and can withstand harsh environmental conditions. However, this powder coating process is expensive and breaks down when it comes in contact with UV rays.?
Conclusion?
A good surface finish is as important as the part itself. Both the manufacturer and end-user enjoy the benefits titanium polishing offers. This is why the process must be done with caution. We have explained the process of titanium polishing and its uses in various industries. Feel free to contact us today to enjoy our premium part-finishing services.
FAQs
Can you polish old titanium parts
Yes, polishing old titanium parts makes it as good as new. However, it is important to clean the part with a cleanser. You do this to remove the buildup of grease that may interfere with the polishing process. However, for deeper scratches, a professional may need to fill them before polishing.
What type of sandpaper works on titanium?
Generally, you can use sand papers made of aluminum oxide or silicon carbide for polishing. But because titanium is a strong metal, professionals recommend any grade of aluminum oxide sandpaper.
How do I choose a buffing wheel for titanium polishing?
There are different types of buffing wheels ranging from soft to the very coarse ones. Because they all have different buff hardness and stiffness, the desired surface finish determines the buffing wheel used.
