Mind Smith are weapon master who has developed latent mental power, unlike psi warrior who uses their psionic power to enhance their martial prowess; a mind smith used their focus their mental manifestation on the weapon itself. 

writer note: this is class is a tribute to the soul knife class in 3.5, and in the spirit of 3.5 its going to be a subclass about stacking passive modifier, so there will not be any spell casting like ability. basically its build your own magic weapon, and honestly i dont think its a very strong class as 90% of this class's power can be replaced by a items. still the souls knife wasnt a strong class either and was entirely out classed by the basic fighter in 3.5 so i suppose the spirit carry on. 

Level 3: Mind Blade

Summon up to two weapons with the form and stats of its mundane counterpart, however it will appear with a glowing hue covering the item making it difficult to discern any detail.

when you roll initiative, or using a bonus action, you can manifest up to two weapon, or one weapon & one shield, of your choosing in either one of your hands as mind blades
the mind blades uses your concentration to continue exist in reality and disappear once your concentration ends.

you can create range weapon with mundane ammunition and throwing weapon gain an additional return enchantment feature.

P.S.:you mind blades has to have a mundane counter part that exist in the PHB, or in a third party published book, or even a modified version of the previous dnd edition. stating the obvious don't create a super op weapon that you made on the spot. that's what the next feature is for. 

Level 3: Psychic Forge

Your weapon gains magical enchantment at different character levels. +1 at level 5,  + 2 at level 10, +3 at level 15.

In addition you can modify your weapon with an additional one tag in its weapon property or weapon mastery, at a cost of one damage step.
it must not be vice versa to gain extra damage, and the modification must be the same on both weapons.
For example, you can create a finesse long sword but its damage dice is 1d8 two handed or 1d6 one handed, and your second weapon in your other hand must also have finesse trait and have one less damage dice. 

at character level 10 you may add a second tag without the damage step cost. which mean you can have a great sword with both graze and cleave weapon mastery that deal 1d10 damage.
(dont ask me how does this work, it work the way you think it works.)

Level 7: Actualization

You are now able to summon your mind blades at will with a free action instead of bonus action and removing the need for concentration. 

Your mind blades became fully realized removing the glowing hue and become complete indistinguishable from real weapons, able to mimic real materials such as sliver, cold iron, or adamantium, and taken on properties of those material. in addition instead of weapon you can also manifest a single simple tool of your choosing such as a shovel, crowbar, rope, or anything else at your GM's discretion.   

your mind blades still have only two weapon limits any attempt to summon more will cause your previous mind blades disappear.  

Level 7: Sharpen Senses

use an action to concentrate your mind to enter a state of sharpen senses, gaining two the following feature:

• Blind sense up to 30ft.
• +2 Ac.
• advantage on one skill check of your choice
• advantage on one saving throw of your choice
• +5 ft reach on your mind blades (reach weapon gain up to 15ft)
• gain temporary HP base on your class level+proficiency.
• able to cast detect magic at all without material component.
• as an action once per 1d4 round you can deal double your mind blades damage to a all creature in a 30ft cone.

you can remain in sharpen senses for 10 min, however you must end your concentration at the end of combat. and you can only uses this feature base on your intelligent modifier per short rest. 

Level 10: Elemental Blade

you prepare two sets of elemental blade you can switch to when you roll initiative, or using a bonus action.

Once per long rest, you can prepare one damage type of the following to be added to your mind blades: fire, cold, lighting, thunder, and psychic; akin to psychic forge they must also be of the same damage type to both your mind blades. this bonus damage is only added if you are in a sharpen sense state.  

The damage dice of Elemental blade will be one step lower on the damage dice of your mind blades, with the exception of 1d4 weapon or less will have a flat +2 damage.
example: If your have a great axe, your elemental blade damage dice is 1d10, great sword 1d10, halberd 1d8, long sword 1d6, short sword 1d4, dagger flat +2, etc, etc, etc,

Level 15: Tempered Edge

Your elemental blades gain one permanent enchantment of the following:

• Keen: your weapon able to critical hit on 18, 19, and 20
• Speed: you again one extra attack
• Bane: pick a creature type you, gain a extra 2d6 on you weapon's normal damage type again that creature. (you cant not change the creature type unless you reset your enchantment)
• Elemental Burst: you gain an extra damage dice on your elemental blade, in addition on upon critical hit your deal the full elemental damage to the near by creatures excluding yourself in a 10 ft radius 
• Vampiric: when you hit a creature you gain 1d4 hp.
• Merciful: same with elemental burst however all of your mind blade damage is converted to radiant damage, and your mind blade can not deal a killing blow only able to reduce HP to zero. 
• Unholy: opposite of merciful, all your mind blade damage in converted to necrotic, any damage that drop the creature to zero hp will kill them instantly. 
• Ghost Touch: able to ignore the damage resistance on incorporeal creature. (apparently ghost touch isn't a thing in 5e so.... any other better idea to implement this let me know)
• Distortion: when you make a range attack with your mind blade you ignore all cover & range penalty. (if you can see it you can hit it.)
• Draining: when you hit a creature deals 1 point of Constitution damage on critical hit you deal 2 point of constitution damage.

you can reset you enchantment if you spend a consecutive 30 days of down time.
P.S.: you don't have to dedicate the entire time to do this, as long as you spend consecutive 30 days of down time, this is only to keep the player from change it every session. conversely the GM can say they are only allow to switch X amount of time per campaign and let the player decide when and how. 

Level 18: Mind, Body, Soul

you again advantage on your concentration check in addition when you taken any damage that is 10 or less you automatically succeed the concentration check. 

you also gain total of three Sharpen Senses bonus when you concentrate.

you also gain a total of two Tempered Edge enhancement, however you can only reset one enchantment at a time.