In the world of CNC work, dust and fume control, along with proper ventilation, hold the spotlight. They’re not just essential for the well-being and safety of everyone involved, but they also play a starring role in the long-term performance and condition of your equipment.
Neglecting to implement adequate dust collection and ventilation measures is like inviting health issues to crash your party while sabotaging the quality of your work. So, it’s paramount to ensure your ventilation system is well-orchestrated.
But wait, there’s more! If you want to elevate your game and minimize the presence of dust, fumes, and smoke when operating a CNC plasma machine, let’s explore two standout options: the water table and the downdraft table. They each bring their own flair and quirks to the stage. Let’s dive in and uncover their key differences, along with the primary advantages and disadvantages of each.
What is a water table?
A water table in CNC plasma cutting consists of a water tank positioned beneath the cutting surface. As the material is cut, debris and smoke are pushed beneath the surface and into the water. This helps to cool the debris sinking into the water while trapping any fume and smoke particles. The water also reduces heat levels, minimizing warpage and allowing parts to cool quickly for immediate use.
While basic water tables are just tanks filled with water, utilizing a table with adjustable water levels enhances smoke extraction and reduces noise. A large chamber with openings along the bottom edge allows air to be trapped inside. By controlling the compressed air flow through valves, the water level can be raised or lowered as needed.
Water Table Pros:
- Costs less than a downdraft table in terms of running costs
- Provides better fume control, which can reduce smoke and dust by 90%
- Does not require a dust collector for most areas
- Improved edge metallurgy on certain components (stainless steel parts)
- Forces particles and fumes into the water, preventing them from dispersing in the environment
Keeps parts cooler, which can be advantageous in instances where material warping is an issue
Water Table Cons:
- Not compatible with some plasma cutting surfaces
- Produces hydrogen bubble buildup with aluminum cutting, creating a safety risk
- Risk of water splashing onto the part, which leads to increased edge roughness and dross
- Water needs to be treated frequently, with periodic disposal and draining required
- Because of slower cutting speeds, a water table is less productive than its downdraft counterpart
What is a downdraft table?
A downdraft table operates by directing airflow downward through the table, effectively drawing dust and fumes away from the cutting area and out of the workshop through a ventilation system. Compared to water tables, downdraft tables may have a higher initial cost and require additional equipment, but they offer the advantage of being easier to maintain due to the absence of water.
The mechanics of a downdraft table are quite straightforward. As a plasma cutter works its magic, most of the resulting smoke is pushed down below the plate. The smoke then exits through the bottom of the cut and disperses outward. The airflow created by a blower or fan ensures minimal smoke escapes. For smaller tables, a single-zone downdraft table is typically utilized, featuring a single open area under the slats and a single duct connection.
However, when dealing with larger tables, a zoned downdraft table comes into play. This table has divisions called sectors or zones. A duct runs along the length of the table, equipped with doors or dampeners in each zone that open and close according to the gantry’s position. This allows the blower to pull smoke only from the specific zone being cut, reducing the required blower size and significantly enhancing efficiency.
Downdraft Table Pros:
- Comes with enhanced fume control that reduces dust and smoke by 70-90%
- Makes disposal of collected dust and particles quick and easy
- It can be used to cut an array of different metals
- Doesn’t require a lot of maintenance (fume systems have their own maintenance)
- Easier to clean and extend for expanded production
- No need to adjust water levels (and worry about splashing or leaking)
Downdraft Table Cons:
- Consumes more power due to the fan/pump operation
- Requires more time to cool parts before using or handling
- Filter needs to be changed regularly
- Removing or adjusting certain parts is more challenging
- Increased heat that raises the risk of warpage
- Higher upfront costs due to additional equipment (dust collector, fans, etc.)
Looking for the best tables for metal cutting? Squickmon’s offers a range of high-quality CNC plasma tables ideal for producing ready-to-install parts. No assembly required, compact footprint, user-friendly software—our offerings provide these perks.
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