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Frequently Asked Questions


Get to Know Us

How long have you been in business?

We’ve been in business since 2008. Originally under the CNC Router Parts name, we became Avid CNC in 2019. Simply put, we’re avid about CNC, and we think our name should reflect that!

Are you related to CNC Router Parts?

Since 2008 as CNC Router Parts, we’ve been passionate about our mission to provide professional machine tools at an exceptional value that are accessible to everyone.

In 2019 we changed the name to better reflect our business. Avid CNC is a new name that represents the excitement and enthusiasm that we bring to this mission every day.

Simply put, we’re avid about CNC, and we think our name should reflect that.

Our team, leadership, mission, and commitment to our customers will all remain the same, just with a new name as we continue forward with exciting products and innovation.

Where are you located?

Good question! We're in North Bend WA (close to Seattle) in the good ole US of A.

Do you have a warranty?

Avid CNC offers a 1-year warranty on all components against manufacturer defects. This includes both mechanical parts and electronics.

How does your support program work?

Our technicians are available for phone, email, and screen-sharing support. We are based in the Pacific Time Zone and our hours are Monday - Friday, 8am - 4pm.

For the best service we recommend emailing us at support@avidcnc.com or contacting us through our Contact Us form. This helps us get you in touch with the right person and the right information.

If you need or prefer to call, our phone number is +1 425-200-5037.

Do you ship internationally and how much does it cost?

We definitely do! We ship components and machine kits all over the world, and have multiple service offerings available for our international customers. We are also happy to work on custom shipping quotes to deliver items cost-effectively.

To get a shipping quote, just create a cart and start the checkout process. You will have the opportunity to review shipping costs prior to placing your order. In some cases, only UPS will be listed as an option due to odd lengths and sizes that the USPS calculator can't reconcile on its own. In this case, feel free to contact us and we can put together a custom shipping quote.

If you have a larger order or machine kit in your cart, these sometimes cannot be economically shipped via standard courier service, so the price you see may be extremely high. Please Contact Us if this is the case -- we can typically ship these larger and heavier items via air freight to your nearest major airport. Just let us know which airport is closest to you, and we can usually get a reliable quote within a day or two.


Machine Fundamentals

Will I need a computer to operate Mach4?

Yes, we recommend using a dedicated PC to serve as your machine's CNC controller.

The recommended specifications are:

  • Windows 10 (preferred), Windows 8, or Windows 7 (64-bit) operating system
  • Ethernet port (or Ethernet adapter)
  • 1GHz CPU
  • 8GB RAM (16GB recommended for Windows 10)
  • Intel or AMD processor, avoid Atom-based netbooks, which tend to be a bit too under-powered
  • Minimum screen resolution, 1920 x 1080 (recommended)

More information

Do you have instructions for assembly of the machine?

All of our assembly instructions can be found here: Avid CNC Instructions

Can I expand my PRO machine at a later date?

Yes, we offer expansion kist for a range of sizes. Please Contact Us.

Can I get more gantry clearance on my machine?

We get a lot of requests for a taller gantry on our machines. While we extend the riser extrusion to provide a taller gantry on our PRO Series Machines, there are several things to consider before going this route.

Machine stiffness

The z-axis is typically the weak link in any gantry style machine with a moving z, as this is the only cantilevered axis (supported on only one end) in the system. With a taller gantry, the z axis needs to extend farther to reach the work bed. For a cantilevered beam, stiffness is a function of the inverse of the axis length cubed, so even a slightly longer z can make the axis significantly less stiff, which can lead to deflections in harder materials and increased vibration while cutting. For materials like foam and balsa, this is less of a concern, but if your main cutting will be in wood or aluminum, cut quality can suffer significantly.

Tooling

A longer z-axis often requires extremely long tooling to fully take advantage of the travel, especially if there are steep concave portions in your design where a router body cannot fit. These tools can be very expensive and can suffer from vibration issues.

Other choices

In most instances, the desire for a longer z is because the final workpiece is taller than the standard travel we offer, but there are alternatives to a longer z travel:

  • Layering The first strategy we suggest is to cut your part in layers, with CNC'd indexing holes to align the layers. This requires far less z travel, and also removes risk by turning a long machining program into more manageable segments. It can also allow you to add undercuts or other features typically not available in standard 3-axis machining if the layers are segmented properly.

  • Lowered Bed In some cases, while the workpiece itself is taller than the standard travel, the actual height delta of contours in the piece is less than the z travel of the machine. In this case, rather than extending the gantry and z travel, more room can just be provided for the workpiece. We can potentially customize the frame of your machine to provide a lowered table if your application requires this.

If you have parts that require a taller gantry, we're happy to discuss the best way to accomplish this on your machine. Just Contact Us and an applications engineer can walk you through various options.

How accurate will my machine be with your parts?

This is a difficult question to answer with a single number, as the accuracy of a machine is dependent upon multiple factors, including the machine size and design, the components used, and the time and care taken during assembly.

That being said, we can make some generalizations based on our own tests and on data from our customers. In general, accuracy of +/-0.005” can be achieved on cuts without too much trouble in a localized area. Repeatability is typically better, and on well-tuned systems, repeatability of 0.002” or better has been reported.

One specific area of concern related to accuracy is backlash. Backlash is positioning error caused when an axis switches direction. If the direction of rotation changes, any lag in the change of direction in linear motion is not seen by the system and results in positioning error. On both our R&P drives and Acme screw based systems, properly setup systems have very low amounts of backlash, typically less than 0.001” in our PRO setups. To put that in perspective, that’s about the thickness of 1/4 of a sheet of notebook paper.

One of the most important design aspects of a machine that impacts accuracy is the height of the z axis. The z is the one cantilevered axis in a machine, so deflection and vibration are highest here. Limiting the length of the lever arm of the z is by far the best way to achieve superior accuracy. For light materials like foam and balsa, higher z axes are possible, but for wood or aluminum, minimizing z height is important.

Should I choose NEMA 23 or NEMA 34 motors?

The decision between NEMA 23 and NEMA 34 motors is primarily a decision about productivity -- NEMA 34 motors can remove material at a higher rate using higher feed rates and deeper cut depths.

The style of motor you choose is not the determining factor in what materials can be cut -- this is far more a function of the mechanical stiffness of the machine doing the cutting, as well as proper speeds, feeds and tooling. With our machine kits, either of our motor packages can cut hardwood, plastic, and non-ferrous materials such as aluminum.

Motors serve to accelerate and decelerate components of the machine (such as the gantry or z axis), as well as to push the cutting bit through material. NEMA 34 motors can take deeper passes through material and improve cutting speeds, especially on larger machines.

Generally, if you are using a machine for regular production work, higher power NEMA 34 motors will provide a fast return on investment. However, if you are primarily doing small production runs or prototyping work, NEMA 23 motors will likely be sufficient.

What is the difference between the PRO and Standard Series?

Our Standard series machines make use of affordable components such as Acme lead screws and radial bearings to provide an exceptional value. Our PRO series machines feature higher-performance components such as profile linear guides, precision ballscrews, and our PRO rack and pinion drive system. These differences yield some important practical advantages for PRO:

  • Easier to assemble and maintain
  • Increased precision, enabling superior part tolerance and finish quality
  • Stiffer machine, allowing for faster cutting and rapid speeds and greater z clearance under the gantry
  • Higher load capacity for larger cutting tools

The PRO series is also designed with expansion in mind, so smaller machines can easily be upgraded to larger work areas in the future.

Which is better, a screw or rack and pinion drive?

The short answer is that both are good for different applications. Each has its pluses and minuses:

Price: Acme is typically less expensive, even in multiple start systems.

Maximum Travel: R&P is required for longer axes. The main reason for this is that screw-driven systems are susceptible to “screw whip”, which is an off-axis motion that worsens the faster a screw rotates. For ½” screws (even multiple start screws, which fare much better due to their higher ratio of linear travel per rotation), the critical speed of rotation makes axes much over 4’ in length impractical. Larger diameter screws can be used, but since rotational inertia is a function of diameter squared, much larger motors are then required to achieve acceptable speeds.

This is where R&P really shines. The system can be used to create axes of arbitrary length, limited only by the length of the linear rail guiding the system. Racks are typically available in 6’ and 12’ sections, and if necessary can be spliced to create extremely long travels. The fixed cost of the drive system and the relatively low cost of cold rolled steel and gear rack make the cost per foot of travel highly competitive for larger travels.

Accuracy: Many people assume Acme is more accurate than R&P, as a screw drive typically has more resolution than our R&P units. Indeed, in theory, a ½-10 single start Acme screw paired with a 10x microstep driver will have an effective resolution of 0.0001”, whereas our NEMA 23 R&P with the same driver has an effective resolution of around 0.0005”. However, both of these resolutions are more than adequate for large format cutting, and inaccuracies at other points in the system (such as screw lead error and backlash) make these differences more or less irrelevant.

Speed: There is an appreciable difference in speed between the systems due to gearing. The R&P is geared more aggressively to better utilize the low-end torque of stepper motors, and is also more mechanically efficient than Acme screw systems. Because of this, it is capable of much higher top speeds (rapids of 600 IPM+ for some NEMA 23 systems and 1000 IPM+ for NEMA 34 systems) than even multi-start Acme. That being said, for shorter travels, this higher speed is rarely realized, as there is insufficient room to accelerate to these speeds, so in this case, Acme can be a good and economical choice.

Other Considerations: R&P systems do have a moving motor, and hence require more cable management than an Acme axis, which typically can have at least one stationary motor. Another consideration is that it is difficult (albeit not impossible) to do a center mount R&P unit, so most R&P systems are dual drive on the long axis. Lastly, for z axes, R&P is not really appropriate, as it can be easily back-driven when the power is off, and can cause the axis to fall in an uncontrolled fashion. This can be controlled with a gas spring or other apparatus, but the cost and complexity is rarely worth it.

Summary: Choose R&P for axes that are 4' or greater in length, or for an axis you might want to upgrade in length later on -- it will be faster and will alleviate trouble with whip. For shorter axes, choose multi-start Acme to save cost.

Why do your R&P units use a belt? Why not a direct drive?

While it is possible to drive a system with a gear directly mounted on the motor shaft, there are two severe limitations this introduces.

Torque: First and foremost, without a reduction (like that in our belt drive systems), you will lose the mechanical torque advantage these systems provide. As an example, for a motor putting out 300-oz*in of torque, with a 1 inch pitch circle gear, a direct drive system will put out about 37 pounds of force, compared to over 100 pounds with our 3:1 belt drive reduction. Stepper motors do lose torque as they spin faster, so reductions much beyond this are not recommended, but with no reduction much of the motor's usable power is not effectively leveraged. A smaller pitch circle gear can provide higher forces, but gears smaller than our current pinion do not effectively keep two teeth engaged with the rack, leading to backlash and lost motion.

Resolution: With a 1 inch pitch circle gear, without a reduction the linear motion per rotation is pi * diameter, or 3.14" per revolution. With typical stepper motors that have 200 steps per revolution, this leads to an effective motion per step of 0.015" (0.4mm), which is quite coarse for CNC applications. While 10x microstepping reduces this to 0.0015", microstepping can't be relied upon for accurate positioning between steps, so a direct drive system will leave visibly "stepped" motion. In contrast, with our 3x reduction, these steps are significantly reduced, and because there is less load on the motor, microstepping is also more effective, leading to smoother, higher resolution, and significantly more accurate motion.

Why should I buy your motors? Company XX has higher torque motors.

We get this question a lot: "Company XXX sells motors with a super high stall torque (oz-in) rating -- won't I get better performance from these higher torque motors"? The answer may surprise you!

Unfortunately, the main statistic advertised on stepper motors is probably the least useful of all -- stall (or holding) torque, which is the torque the motor puts out when it is not moving. This isn't terribly helpful, as your motor isn't doing any work when it's standing still! All steppers run at less than their stall torque, so what's far more important is the usable torque of the motor throughout its RPM range. The "flatter" this torque curve, the more usable force (for accelerating and decelerating) you'll get out of your drive system.

All stepper motors also put out less torque the faster they rotate. There are two key values that you should be looking for in a motor that influence its performance: current and inductance. First of all, you should look for a motor with a current rating that is less than or equal to the current rating of your motor driver. Motor torque scales linearly with current, so if you are (for example) driving a 5A motor at 3.5A (the maximum the G540 drive can put out), you are only getting 70% of the motor's rated torque. All other things being equal, a 425 oz-in, 5A motor running at 3.5A will actually achieve less torque than our 420 oz-in motors running at 3.5A.

The other important thing to look for is the motor inductance. The lower the inductance, the slower the motor builds up "back EMF voltage", which reduces the torque of the motor. While higher inductance can be overcome with higher voltage power supplies, this adds extra heat and expense to a system.

We invite you to look at competitor offerings, and see for yourself why our motors are better. We offer motors that are matched to the current ratings of the drivers we sell. Our motors are also low inductance, 2 mH for our 960 oz-in motors and 3.0 mH for our 420 oz-in motors, both of which work great with commonly available 48V supplies.

So don't fall for the hype -- with our motors, we've had customers gain 3x speed increases over motors with higher rated stall torques. We've tested our motors and competitor motors with our mechanical systems to find the best value for you. Buy from a name you can trust to get the most out of your machine.


Initial Setup

What are the power requirements for your machine?

All of our NEMA 23 and NEMA 34 electronics are dual voltage, and can be set to run of either 100V-120V or 200V-240V AC single phase power by configuring the voltage-range selection switch on the main power supplies. All systems are compatible with either 50 Hz or 60 Hz power.

All of our Plug and Play Spindle / VFD Systems require 200V-240V AC at either 50 Hz or 60 Hz. Our 3 HP spindle runs off single-phase power and our 8.7 HP spindle runs off 3-phase power (or single-phase with reduction in peak power to 6.5 HP)

For detailed power requirements, please reference our technical documentation:

What tools do I need to assemble a machine?

View our list of recommended tools for the follow machine series:

Can I get more gantry clearance on my machine?

We get a lot of requests for a taller gantry on our machines. While we extend the riser extrusion to provide a taller gantry on our PRO Series Machines, there are several things to consider before going this route.

Machine stiffness

The z-axis is typically the weak link in any gantry style machine with a moving z, as this is the only cantilevered axis (supported on only one end) in the system. With a taller gantry, the z axis needs to extend farther to reach the work bed. For a cantilevered beam, stiffness is a function of the inverse of the axis length cubed, so even a slightly longer z can make the axis significantly less stiff, which can lead to deflections in harder materials and increased vibration while cutting. For materials like foam and balsa, this is less of a concern, but if your main cutting will be in wood or aluminum, cut quality can suffer significantly.

Tooling

A longer z-axis often requires extremely long tooling to fully take advantage of the travel, especially if there are steep concave portions in your design where a router body cannot fit. These tools can be very expensive and can suffer from vibration issues.

Other choices

In most instances, the desire for a longer z is because the final workpiece is taller than the standard travel we offer, but there are alternatives to a longer z travel:

  • Layering The first strategy we suggest is to cut your part in layers, with CNC'd indexing holes to align the layers. This requires far less z travel, and also removes risk by turning a long machining program into more manageable segments. It can also allow you to add undercuts or other features typically not available in standard 3-axis machining if the layers are segmented properly.

  • Lowered Bed In some cases, while the workpiece itself is taller than the standard travel, the actual height delta of contours in the piece is less than the z travel of the machine. In this case, rather than extending the gantry and z travel, more room can just be provided for the workpiece. We can potentially customize the frame of your machine to provide a lowered table if your application requires this.

If you have parts that require a taller gantry, we're happy to discuss the best way to accomplish this on your machine. Just Contact Us and an applications engineer can walk you through various options.

What is the maintenance schedule for my machine?

This will vary depending on usage, but in general we recommend greasing the ballscrew axis, linear bearing blocks, and gear racks on your machine every 2-3 months.

You can find more information here:

In addition, the pinion gear is wear item and will need to be replaced periodically to avoid backlash. Our Spare Parts bundles are a great way to have critical spares on hand.

What does tramming mean?

Tramming is the process of adjusting the cutting tool (spindle or router), so that it is perpendicular to the table surface (the XY plane). For more detailed information, see our Tramming Instructions.

Can I expand my PRO machine at a later date?

Yes, we offer expansion kist for a range of sizes. Please Contact Us.