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CNC Router Sacrificial Beds
I’m hoping one of you cleaver folk can help me out on this one.
I’ve seen the below sacrificial beds on tekcel machines and believe this is simple enough to make, it looks like a 10mm sheet that has larger holes cut 5mm down and then a hole that goes right the way through the main larger hole. I have asked Tekcel if they sell these but I kept getting told NO!
Any ideas on how to make one of these. I have a bed area of 3m x 2m so guess I could need a couple of sheets to join together to create this type of things.
Anyone wish to share CNC bed options, I’m having issues with suction at the moment and getting rather annoyed. I walk around most trade shows and always notice the CNC machines have great suction.
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11 Replies
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James
MDF is not really the best board because it will allow suction through the board so it means you would lose suction, you need a phenolic board. I don’t know what you have already but will try to pop in and see you in the next few days and then may be able to suggest something.Kev
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We have an identical Teckcell router to the one in your picture.
The picture you posted is NOT the sacrificial board. A sheet of MDF goes on top of that, and the vacuum "bleeds" through the mdf…..
It is made from a product known as Comaprint in the local trade. Easy enough to drill and pocket with a cnc.
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Gert
Thanks for your reply.
Is Comaprint known by any other names?
I’m trying to course this material but not having much luck
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hiya i used to use one of these when i worked for a company who contracted all the NHS signage and the bed was made from Foamex 12mm i think , with a 2mm sacrifical sheet made from mdf placed on top, if you want to increase the suction block the rest of the holes on the bed which are not used with application tape or off cuts of plastic you have lying around this will increase the suction to the main area you are routing. This may be or may not be of any use but i hope it is.
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Darren
Thank you for your comments
I’ve always used a 22mm MDF board for my main CNC bed it’s a marine grade board which we skim down to get a perfect flat layers.
This methods has worked very well for us but walking around trade show I see people cutting smaller and intricate objects and having no issues with suction.
I have a 3m x 2 m cnc with ATC it’s great it has zones that can be turned on and off for suction strength, I think my problem is the CNC bed I’m using isn’t to great.
My thought are trying and get a good thick foamex board skim it around 0.3mm and add the holes and pockets create my own CNC bed.
I’m hoping my suction increases
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James
I have always used mdf for the plenum but you have to seal it with at least 2 coats of pva glue cos its quite porous. im pretty sure foamex is porous as well, and harder to seal…if its the same stuff im thinking it is…they call it signex over here.Simon.
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quote James Sahota:DarrenThank you for your comments
I’ve always used a 22mm MDF board for my main CNC bed it’s a marine grade board which we skim down to get a perfect flat layers.
This methods has worked very well for us but walking around trade show I see people cutting smaller and intricate objects and having no issues with suction.
I have a 3m x 2 m cnc with ATC it’s great it has zones that can be turned on and off for suction strength, I think my problem is the CNC bed I’m using isn’t to great.
My thought are trying and get a good thick foamex board skim it around 0.3mm and add the holes and pockets create my own CNC bed.
I’m hoping my suction increases
why do you use 22mm MDF !!!
use 4 /6 mm, the reason your losing suction is the pump cant suck well enough through that thickness of MDF.
change to 4mm and i bet you cant lift the sheet up off it -
Whenever I’ve been into a AXYZ showroom Ive seen them use boards as thick as 25mm and actually advice of it.
Alot of the CNC forums have also advised 25mm boards as an option.
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quote James Sahota:Whenever I’ve been into a AXYZ showroom Ive seen them use boards as thick as 25mm and actually advice of it.
Alot of the CNC forums have also advised 25mm boards as an option.
Give it a try 🙂
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The marine grade board you are using is likely to be much denser than a cheap internal grade board, that may be why your having problems with hold down.
I would try a thinner board as Ian suggests.
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Sorry for the late reply, but things are hectic……
Few pointers: Yes, you can use thick MDF, but I normally use 12mm. I have noticed when milling 32mm MDF, I can still feel suction through it. If the 12mm sacrificial is included, that is more than 40mm of MDF!
You HAVE TO skim both sides. Firstly, it prevents the MDF from curling up, secondly, the smooth/gloss surface also restricts the flow
Our cnc’s got 2 HUGE pumps, but small stuff is still a problem. I normally use scraps of cheap 3mm ACM and staple it around the workpiece to prevent it from moving.
Keep the filters clean.
Beware of oil contamination. It "blocks" the MDF. For this simple reason, I now mostly use only alcohol in the mister, and only use oil on 10+ mm thick Alu.
Do a regular "fly cut" – smooth surfaces work better with bleed through systems.
I don’t worry much about blocking exposed areas on the bed. I only open the vacuum handles as wide as the stock is. (ie if the sheet is 1200 x 2400, I don’t block the 600mm exposed on the end. The vacuum pump can flow large amounts of air. The limiting factor is not flow rate. The vacuum pressure stays damn near the same.
TBH, I prefer mechanical fixing to vacuum. Done correctly, it is the safer option. The only reason I use vacuum is because it keeps sheet stock nice and flat, making for accurate grooving. On my hobby cnc at home, I use screws, staples, or double sided tape. At work we typically process up to 30 odd sheets per day, so there the speed of the vacuum system helps. At the cost of the odd spoiled cut…….
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