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CNC router machines can have various components in the basic configuration, and of the options you may apply—the vacuum table. However, why would you need it? How is it beneficial? Today, we will respond to those queries.
What is the vacuum table
This is a special device that was created to fix the materials in one place without additional clamps. In that way, you may avoid any kind of deformation while processing soft or fragile workpieces. The main one here is the pump, which creates a vacuum.
Actually, there are a lot of types of these tables:
- Grid-like. Such a table consists of an aluminum grid of squares with grooves between them. This design provides a high degree of hold-down pressure.
- Porous. In this case, the working area is covered with porous material. This is required for the high-precision work with especially thin and delicate matters. With their help, it is possible to even process foil!
- Hole Matrix. Tables like these have plenty of holes or lengthwise recesses that allow the full perforation of the materials.
- Flip-pod. It is being used when processing huge and bulky workpieces, and for that reason this table has a unique, complex structure. It’s made out of many mobile suction cups; thanks to that, it’s possible to adapt the table for any shape. Also, there is an ability to perforate.
There are other types; however, these are the most popular ones. Vacuum tables that are used for the Wattsan machines have a grid-like structure, and for that reason we will talk about them following on.
Key advantages and disadvantages of the vacuum tables
With these tables you can:
- Fixate almost any workpieces while also assigning the same amount of the pump’s effort along the whole surface.
- Fixate without risks to damage the material or leave marks on it after holding.
- Work fast since time for the material placement with clamps is reduced to a minimum when you can simply lift the piece.
Attention! A vacuum table is not a best choice for your CNC router machine if your main working material has a porous structure or an uneven surface on the side that is going to be laid against the table.
Design specifics
The table is made from plates with a grid of intersecting grooves machined into them. Another key part of the system is, of course, the pump. In our machines, it’s a vortex pump. This type is not very demanding in terms of maintenance and has a reliable design, where only the bearings wear out over time. It also offers a good price-to-quality ratio.
The pump operates on a 380-volt power supply, and depending on the number of pumps and table size, the total power can range from 5.5 kW to 7.5 kW.
Zoning feature
The previously described grid creates zones that are linked by reinforced hoses passing through holes in the plates. Each of these plates is connected to a main vacuum pipeline. This design gives you control over which zones are active and how the pump’s power is distributed: you may direct it to a single zone to boost hold-down strength or spread it throughout 4-6 zones.
Looking at the side of a router, you can clearly identify the number of zones, since there are levers that allow you to change the pump’s power distribution, one for each zone.
This zoning allows you to work with different workpieces on the same table simultaneously and process materials from any side.
Working process
The vacuum table holds the material from below, preventing it from shifting left or right; however, lifting it upward can be done without much effort. While doing so you may imagine yourself being super-strong. Inspiring!
Another important point: if your workpiece has an atypical shape, it’s best to use a sealing cord to improve hold-down pressure. This cord fits into the grooves of the grid table, following the shape of the workpiece. It’s best to trace the shape with a slightly smaller outline. This reduces the area from which the pump draws air, ensuring that even such a piece won’t shift under spindle pressure.
Advices
If you plan to cut material all the way through, it’s best to use a sacrificial altar table made of MDF or PVC. This is placed on top of the vacuum one, and the material itself is secured to it with clamps. A bit more on this: if you’re using a sacrificial table, be sure to mill off 1-2 mm before starting work to level the surface. And if you’re using laminated MDF, remove a layer from both sides, as the lamination blocks airflow and weakens the suction.
Also, keep in mind that the pump is quite loud, but you can deal with this by placing it outside if weather permits. However, we recommend keeping the hose between the pump and the CNC router machine as short as possible, as a long hose can negatively impact the vacuum table’s suction power and weaken its hold.
A final tip concerns the electrical setup. To ensure everything functions smoothly, run a separate cable from the pump to the power source. This is because the machine requires a voltage stabilizer, while the pump does not.
Conclusion
- A vacuum table securely holds workpieces of various fragility and weight, preventing any potential damage. This makes it suitable for working with delicate materials like acrylic or even foil.
- There are different types of tables, with the most common being grid, porous, hole matrix, and flip-pod. Our CNC router machines use grid tables due to their superior holding power.
- The table’s zoned design allows you to control suction strength, making securing more reliable by directing the pump’s power only to selected zones.
- If you plan to drill through workpieces, it’s best to use either a sacrificial MDF or PVC table, or hole matrix and flip-pod types.
