Dust Extraction on PTP Routers

[Scrit]

OK guys. Anyone got any suggestions about how to improve dust extraction on our PTP router? All suggestions gratefully recieved (well, almost)

[ger21]

On my homemade router I plan to blow air into the cutter to loosen up the chips. On our point to point at work, I find that most of the chips get packed into the groove. If I'm trimming an edge, I get pretty good dust collection. Now if you're talking about the chips from boring, most of mine remain lying on top of the workpiece.

Gerry

[Laff Riot]

An engraving spindle with chip extracting head wouldnt work?

[CNCadmin]

Do you heads have brushes on them?

[Scrit]

Each of the router spindles has a 4in brush "skirt" around it, which I replaced this morning - made a bit of a difference, but not as much as I'd hoped for. There is a 120mm flexible hose take-off on each head and there are 2 x 120mm take-offs at the back of the drilling "crown". Drilling operations seem to leave waste materials everywhere, the DX is almost useless on them.

ger21

Thanks for the suggestion about air blowing. I have toed with the idea, but what I find a bit daunting is threading the extra air line and control line through the power/services chains to the gantry front. I use an air jet on our pin router when I'm copy routing plastics, so I guess it should work quite well. On the pin router it reduces the tndency of plastic swarf to weld-back.

Has anyone tried a compressed air vortex accellerator to increase waste pick-up? Seen them on welding extractors and wondered if they would be useable on larger/heavier chips.

Also are brush skirts better or worse than the polyurethane "finger" skirts I've seen on some machines?

[Zephrant]

A little more info on what is not being picked up would help.

What kind of materials?
Dust or chips?
Is the chamber inside the skirt kept clean, and chips are blowing out under the skirt?
What kind of air volume are you pulling?

If you are leaving chips under the skirt, maybe you need more air volume.

Zeph

[ger21]

Sounds like basically yours is the same as ours. Most of the suction is routed to the routers. And when drilling, the head doesn't come close enough to the workpiece to create any suction.


Gerry

[Scrit]

I'm now convinced that the problem isn't air flow. It's design. The gantry has four 120mm hoses and an 80mm hose feeding into a single 225mm hose via a 5-way manifold. This means that at the point at which the manifold starts there is a cross sectional area of 39,740 mm2 whilst the hoses feeding it have a cross sectional area of 50,240mm2. Looks like the airflow is being strangled by poor design. I'm going to try putting three manual blast gates onto the manifold (one on each of the spindle heads) together with replacing that ridiculous 80mm hose by a 120mm. If I then run with three 120mm vents open I'll have 33,912mm2 cross section feeding 39,740mm2 which should considerably reduce the choking, although it may still be necessary to drill some air bleed holes in the manifold. Looking at other PTP machines, this looks like it could be a common problem - and unlike the big shops I can't afford to install a huge dust extractor to try to overcome the inefficiancies of design like this. I'm also considering replacing most of the flexible hoses which run along the sides of the gantry with smooth galvanised steel ductwork to reduce the drag created by the ripples in flexible hose. I'll post my results when I know how good (or bad) they are.

Scrit

[Scrit]

This morning I installed three manual blast gates on the spindle extraction and replaced two (out of three) sets of dust boot brushes. The old ones didn't look too bad, but they were rather stiff with resin from pine and possibly also the glues from MDF/chipboard/plywood. The initial results look to be one heck of a lot better, at least on MDF. I'll know about hardwood when I do a batch next week. The dust extraction is much more efficient with two spindle heads blocked off, even when drilling. I've found that the extraction on drilling is beter when the middle spindle hose is sucking, that way I seem to be getting a 3-point extraction. Still isn't as good as I'd like, but it is better. I think the next thing I'll look at is replacing large parts of the flexible hose with steel ductwork before automating the blast gates.

[smi4motion]

I also would be interested in where I could buy a Packaged spindle/auto tool changer /chip/swarf removal unit. I have seen a few routers with "cyclonic swarf removal" like the Pacer systems but I have yet to determine the maker of the vacuum components.
www.pacersys.co.uk/k.htm