Are Linear guideways overkill in this design?

[8nexus8]

Hello everyone,
Im building a personal project at home which requires a linear movement. The travel distance is only +-5mm, very slow so acceleration, rpm and speed are not relevant here. But I do need high rigidity and very smooth operation. The peak force that acts on the plate (in green arrow) is around 800N and the duty cycle is pretty much random, also, regular working conditions (no vibrations, no room temp and humidity)
The blocks in the pic are MGN7C,
I never designed such a system so my questions are:
Are linear bearing guideways overkill? Should I just go maybe for a dovetail guideway design?
If I go for the bearing route, are 2 enough? should I just go for 2 MGN9C's instead? (assuming of course that they can handle the load and moment operations).
Due to the relatively small baseplate, 4 blocks feel reduntant.

Any other suggestions and input will be appreciated,
Also, any reading material for designing such a system is also welcomed.
Im a mech engineer so feel free to compliate.

 

[3DDave]

It's a packaged solution that appears to cost $13. How much less expensive can an alternative be and how much is your time worth to find it?

 

[Orange_kun]

Not sure if this is relevant, but when designing things with plastic guide bushings, you need to achieve a specific minimum aspect ratio if you're using 4 blocks on a platform, otherwise you risk binding due to overconstraint and bearing play.

IGUS has a good guide about designing with plastic guide bushings. Might be worth a look to check your layout.

Agreed with above - for $13/pc, why look elsewhere?

 

[MintJulep]

very slow so acceleration, rpm and speed are not relevant here.

Uhm....

F=ma

Your m looks pretty small, so a will be correspondingly pretty big.

 

[8nexus8]

I

It's a packaged solution that appears to cost $13. How much less expensive can an alternative be and how much is your time worth to find

It's a packaged solution that appears to cost $13. How much less expensive can an alternative be and how much is your time worth to find it?

It's more about the space constraint, I need it to be as small as possible, adding 2 more rails needs much more space (there are other parts in that assembly not shown which will be affected)

 

[3DDave]

Always good to be scolded over not meeting an unstated requirement.

 

[Orange_kun]

? You don't need more than 2 rails. Mount 2 carriages on each rail. And consider finding some shorter length carriages if things are super close. Or make your platform bigger. Have you calculated the torsional moment that will be acting on the carriages to keep the plate flat when the green force is applied? I don't think you'll want only 2 carriages and the lead screw resisting that.

Or you know, keep drip feeding us information. This isn't rocket science. Design guides for this situation exist.