Introduction to Flat table CNC Machines

by Christine Bergeron, Planit Canada Technical Support 

When it comes to operating and maintaining your CNC machine, having a firm grasp on some best practices can help get you through some of the initial challenges. Christine, one of our awesome Planit Canada technicians, had the first-time CNC owner in mind when she created this beginner’s guide to Flat table CNCs. We want to make sure that you’re ready to roll with your CNC machine, that it’s set up for maximum productivity, that your operators know how to keep it in check, and that your CNC is ready to integrate software when your Planit Canada specialist comes around.

Controller

What is a Controller?

The controller is essentially a G-code programmable controller that offers direction and step outputs necessary for stepper drivers. You could say that it’s the software that’s installed on the CNC’s computer. It is very important to be trained properly on how to turn the machine on, know its origins and movements, create and open programs, change tools and their speeds, and other very important tasks to keep the machine functional.

Is my post-processor the same thing as my controller?

The answer is no. The post-processor is a translator; it takes the information from your CAD/CAM Software and translates it for the controller. Much the same way as no two snowflakes are alike, no two CNC setups are alike.  There are so many variables that we rarely see the same setup on the same machine at one location as we do at another. For this reason, we need to get some code from your CNC to get the proper “translation” from the post-processor. You can think of it as having different accents in the same language.

Spoilboard

What Material should you select?

• This could be either an LDF or MDF panel. The core of this material is porous, but the faces are not, meaning that before using this material, you must flatten both surfaces. This will also make sure that both sides are even.
• If you use a spoilboard without sealing all four edges, you run the risk of bleeding most of the airflow out of the edges and having very little vacuum at the top of the spoilboard where you need it. (We recommend 2 coats of paint to seal the edges.)

How do you flatten your spoilboard?

• Every CNC machine includes a “surfacing” program in its controller for flattening the spoilboard. You must have an appropriate tool; this typically has a wider diameter (face milling cutter), to run the surfacing program. After you run the program, you will enter the new thickness of the board on the controller. Make sure everyone on your team is trained on this topic!
• You will need to flip the spoilboard once in a while. If you leave the sheet on the same side, you may notice that it will warp and make it harder for your pump to keep the spoilboard in position.

Do you need to screw your spoilboard to the table?

• This is your preference! If you would rather not, make sure that your vacuum rubber seal is in good condition and that there is no dust between the table and the spoilboard. The vacuum needs to be maximized. You may want to ask your machine supplier to train your staff on the best practices to optimize the vacuum on your CNC.

What to do if the sheet needing to be cut is smaller than the table?

• If the sheet you need to cut is smaller than the table, you may need to cover the remaining space on that table with small scrap material to maximize the vacuum. Otherwise, the surface that is not covered by the sheet will let the air flow easily and your panel might not be held down properly.

Maintenance

Who is responsible for your machine maintenance?

• Ultimately, you are responsible to maintain your machine. We strongly suggest having a preventive maintenance plan; there are some tasks that your operators will be able to easily do themselves. Daily or weekly maintenance to control the dust, check the hydraulic pressure and fluids, check the lubricant levels, check the seals, check/clean the filters, make sure that the tools are still in good shape, just to name a few, is important. These tasks will vary depending on the type of machinery or desired preventative maintenance outcomes. For monthly, quarterly, and yearly maintenance, you may need a mechanic or a CNC technician.

Should you have spare parts?

• Even if you have a good preventive maintenance plan, it may happen that you’ll need to have essential parts on hand for quick replacement and to avoid the stress of waiting for rush delivery from your part/tool provider!

Keep in mind that dealing with maintenance emergencies and breakdowns comes with a high price tag when you consider lost production, rescheduling technicians, and overnight shipment of parts.

Tools

What types of tools will you need?

The list can be long or short; it will vary on the type of production you have. It can be difficult for new CNC owners to navigate the wide world of tools that are available to them – this is totally understandable!

Here is a basic list of must-haves:

• A flycutter to do the resurfacing of your spoilboard
• A compression bit for the outline cut (typically ½” or 3/8” compression bit)
• 3mm, 5mm, 8mm, 10mm drills depending on the type of hardware you use,
• Down cut tools with various diameter to create the dados or any other cuts that do not cut through
• Miter bits of various angles

If you are machining MDF doors, you’ll have a longer list. Make sure you have enough tool holders with the proper shank diameter for all the tools you’ll need. Also, make sure you get the tool specs from the provider to know their speeds and feed rate. You don’t want to break them, or even burn your table if they’re not running fast enough. As you know too well – friction/wood and vacuum can be a bad mix.

CNC Operator

What does the operator need to master?

The machine operator needs to master these important things:

1. Keep the machine clean
2. Resurface the spoilboard
3. Load tools and set the Tool Length Offset and Set Tool Diameters so Cutter Radius Compensation can be used
4. Load Programs onto the machine
5. Do the daily/weekly maintenance as per schedule

If your CNC machine doesn’t have sufficient positions to have all of your tools available at once, you’ll want to have all the tools ready to go in a toolholder so that they can be readily available as needed.

CNC Integration with CABINET VISION

What needs to be done before the integration?

The following is the checklist we’ll send you before the scheduled integration.  All these things must be taken care of on your end before one of our techs can integrate the CNC cabinet design software CABINET VISION.

• Is the CNC machine up and running?
• Do you have the proper tooling installed on the machine?
• Did you provide a sample code from your machine to Planit Canada with your tools?
• Will the CNC machine be available for running test parts during the integration?
• Does the operator know how to raise the “Z” level for a “dry run” test?
• Does your machine have a loader/unloader?
• Does your machine have a labeler?
• Does your company have high-speed Internet access?

We understand how high your expectations are when you buy your first CNC – and they should be! If you’d like to read a first-hand account of a manufacturers hard-earned experience buying and integrating a new machine, read The Journey to CNC written by Jolanda Slagmolen-Flores, AKBD, General Manager, Casa Flores Cabinetry, Alberta, for the Canadian Kitchen Cabinet Association (CKCA).

References:

https://www.onupkeep.com/answers/preventive-maintenance/preventive-maintenance-on-cnc-machines

https://massesales.com/spoilboards-101/

http://www.cncroutersource.com/cnc-controller.html

https://www.cnccookbook.com/cnc-machine-setup-setting-procedure-lathe-milling/

https://store.allstarcnc.com/