CNC Linear new to cnc

CNC Linear GETTING STARTED

If you are new to CNC's getting started is always a time consuming undertaking to research what it takes to purchase a CNC machine. There are two parts to purchasing a CNC machine that are vital to your selection, 1.) the machine itself and 2.) the CAD/CAM software.

The CNC machine itself has software that is dedicated to the operation of the machine, it takes G code input files and converts it to machine motion. This part of the machine operation is not difficult to learn. Opening a file, setting the XYZ zero points, manual movements, setting fixture offsets, etc. are part of the process of setting up and loading your part on the CNC machine and seeing it cutting your part, this will become so routine that it's like driving a car.

The CAD/CAM software part is probably the area that puts a damper in moving towards purchasing a CNC machine because it has a high learning curve and cost, it is also the area that gets over looked too often. This is the area that really needs to be considered in your quest and probably should be looked at before even purchasing a machine. The consideration should be, am I going to learn the CAD and CAM part or am I going to hire someone to do this for me? CNC Linear has put together a program that will get you started in the right direction by recommending the CAD software to purchase, that is simple to learn but also has the 3D capability to model (draw) a guitar and CAM recommendations that will allow you to assign the tool paths to your part. We also have video tutorials available that will specifically take you through the process of drawing guitar necks, guitar body, etc. both in CAD and CAM. Our program will also go through the fixtures and indexing of the part and the CNC table, we will also cover the vacuum aspect and process.

Once you get through making up your mind on the software portion then you have the CNC machine itself, this becomes very interesting because everybody is competing for your purchase. There should always be questions to ask any CNC manufacturer that will make sense in your mind to what type of machine your getting. Let's cover those in a nut shell;

1. What is the working area in all axis? Will that fit my parts requirements?

You should have a pretty good idea what kind of parts you want to cut on your machine and what the sizes are. However it would also be good to think about how you are planning to hold the part down, this also comes in to play in the working area.

2. What is the overall size of the machine? Will that fit in my shop or work area?

In alot of cases shops may be a garage or a small room, this becomes a challenge due to space requirements. You should consider where you are going to place the machine and where your dust collection system will be (if any). We always recommend that the CNC machine should be the first tool in line of the dust collection intake, that way you can get the best suction possible. It is also highly recommended to keep the diameter of the tube as large as possible at least 6". The other space requirement may be the power source like the spindle that requires 220 VAC.

3. What are the power requirements? Will what I have work or do I need to get an electrician?

This is probably one of the key elements to running your CNC machine. Where the problem occurs is that the area does not have adequate circuit breaker protection. In these cases it would always be wise to ask the experts and have the CNC machines power requirements at hand.

4. What kind of linear rails does it have? Is it round rails or profiled?

Linear rails come in many flavors each has there purpose and each has a different price tag. The important part is how the rail interfaces with the block, either via a friction less sleeve or bearings. Bearings are the better choice due to it's longevity and it also has less friction with better load capability. Round or profiled, this is where all the work is done to maintain accuracy and longevity over the life of the machine. It also effects the price tag of the CNC machine itself. CNC Linear only uses profiled rails.

5. What kind of linear screws does it have? Is it lead screw, ball screw or rack and pinion?

Like the rails there are many flavors to linear screws. Lead screws are the cheaper of the bunch but require more torque from the motor which is very important to how fast the CNC machine will operate. Whereas the ball screw, be it more expensive, will have less torque with greater loads. CNC Linear uses strictly precision ball screws.

6. What is the construction of the machine? Is it steel or aluminum?

Construction of the machine is tricky, it would be best if you had the chance to see a machine in action and give it the old tire test, in other word give it a bit of a bump, you will get a sense of how sturdy and solid the machine is.

7. Where is the control box? Is it attached or away from the machine?

Some machines may have the control box near the CNC machine, this is something to consider in your shop area, because you will need to take into account extra wires and where to put them. CNC Linear has it's control box attached to the machine, keeping wire to a minimum.

8. Are the linear rails and screws sealed for dust?

Dust will gum up a machine very quickly. CNC Linear has seals on all there linear rail and ball screws, plus the Y and Z axis have an additional dust protection.

9. What kind of motors are on the machine? Stepper or Servo

Stepper motors do not have the RPM that servo have but have better torque at lower speed than do servo's. Servo's also need a encoder to operate, called closed loop, whereas Stepper motors are open loop. CNC Linear uses Stepper motors because they are less expensive and they do not have any brushes. We have achieved high speed with the proper pulley ratio's to compete with any small CNC machine on the market.

10. What kind of controls does it have? Is it proprietary to the Mfg or is it off the shelf?

CNC Linear does not use any proprietary software controls, it uses Mach3 which is a machine control software that has been proven over and over again.

11. What is the maintenance procedure? Is it easy to maintain?

Maintenance is very important over the life of the machine, it's like keeping the oil changed in your car. Keeping this in mind, the manufacturer should have a maintenance schedule and also MTBF (Mean Time Before Failure) procedure.

12. Will the machine work for both router and Spindle? What is involved to upgrade to Spindle?

This is a good point, some machines may not have the capability of mounting a spindle. This is something to watch for because spindles weigh about 18 lbs. If the machine can handle a spindle, what is the mechanism the will prevent the Z axis to back drive? CNC Linear can handle a spindle and also has a gas spring to prevent the Z axis to back drive.

13. What is the HP of spindle motor?

We recommend a 3 HP motor at 18000 RPM. Spindles are great because you can control the RPM which is important when you do drilling operation.

14. What is the size ER collets? ER20 or ER25

Check to make sure that your spindle can hold a ER20 or ER25 collet. You can also purchase a collet set from 1/8" to 5/8" in 1/8" increment. The Spindle that we sell is for an ER25 collet.

15. What kind of bearing system does the spindle have? Single or double?

When you talk to the MFG, ask if the spindle has single or double bearing system and type of bearings. Single bearing are designed for routing only where as a double bearing system is for routing and drilling. The spindle that we sell does have a double bearing system.

16. How much assembly is required when I get my machine?

The other area to consider is when you get your CNC machine how much assembly is required and does in take some sort of alignment. CNC Linear machines come apart at the gantry with 4 screws on each side and two connectors, there is no alignments required.

17. What are the options? Spindle, Computer, Stand, etc?

In most cases most MFG's have options. You may want to purchase the basic machine and upgrade later, make sure you ask if there are any upgrade costs involved in the basic machine, such as additional wire/connectors. We do have a small cost if you were to purchase the machine with option of future spindle upgrade, we have to incorporate the connector and wires for this upgrade.

18. Does it have 4th axis capability?

The 4th axis is designed so that you can rotate your part is parallel to the surface of the CNC machine. We have this option, it requires a motor driver and 4th axis module.

19. Does it have additional inputs?

Additional inputs (connector) are important so that you can attach a tool height sensor, or digital probe, etc.

20. What kind of materials can this cut? Wood, plastic, aluminum, brass, shell?

The type of materials that you want to cut is how the CNC machine is constructed, If you are planning to cut all these materials, it would be best that the machine you select has some mass.

21. What is the speed of the machine?

Speeds, in inches per minute are important to some a degree. Non cutting speeds are more important to big machines, but not as much to smaller machines, in fact sometimes it's harder to stop during high speed. One thing remains the same in all CNC machines is that you can't cut at high speed.

A CNC machine regardless of how big or small it is still a major purchase. The more you ask questions the more you validate your purchase. The reason for buying a CNC machine is that you can get into cutting parts as quickly as possible, that is one of the reasons you need to look into what the manufacturer has in the way of support system.

If you have any more questions or you what to elaborate on a particular subject, please feel free to call or e-mail me

chris@cnclinear.com

360 697 6828