This is a friendly build focus on full melee damage.
Most mods are pretty easy to get, and you can purchase from Loid in regular basis and father during Operation Orphix Venom.

People without [Necramech Streamline] or no problem running out of energy, you can use [Necramech Blitz] for bash damage or [Necramech Efficiency] for extra mobile.
People with out [Necramech Steel Fiber], I would use [Necramech Rebuke] as cheaper option and as extra fail safe. This mod will give you 3 secs of electrify when shield break (not Tower Shield), that way you can Meat Hook enemy to prevent from fatal damage.

There are couple idea I would like to share:

*Improve Melee Damage

• Necramech Pressure Point
• Necramech Intensify
• Necramech Fury
  Pretty Basic, mods that will provide extra melee speed and damage, and even your 4th Ability!

*Protection Cycle

• Necramech Augur
• [Necramech Rage]
  [Bonewidow] will be tanking loads of damage in close combat and CQB.
  Those two mods will allow your bonewidow to stay in battle longer.
  Damage Health -> Energy -> Shield + Put up tower shield with Ability 2.

*Mobile

• [Necramech Hydraulics]
  During Operation Orphix Venom, certain Orphix are in pretty high ground.
  You can actually attack it by climb up from behind, but with this mod it will save you some time.

*Fail Safe

• [Necramech Repair]
  During Swing of melee, you could catch big damage hit, and this mod will prevent you from destruction.

Abilities:
Ability 1 Meat Hook -
It doesnt seems to describe in the game, but it has lifesteal while having an enemy on hook. This ability allows you to get fully repaired.
Grabbing certain big enemies like moa, Nox or Sentient will heal you right the way!

• When sentient is dancing with laser, you can use meat hook to stop it.
• You can throw an enemy out to space and he/she will never come back!

Ability 2 Tower Shield -
Basically, its an extra steel plate without weight, and its in front of your tank.
Always good to keep it up.

• The shield has 4xxx health when fully leveled and benefit from Necramech Intensify, and it become 56xx when Necramech Intensify + Necramech Steel Fiber are attached.
• Whenever tower shield is destroyed, you could switch to Meat Hook to keep your health up.

Ability 3 Firing Line -
Can put enemies in the line and stun, but cant stop sentient with its fancy laser dance. Dont Use it.

Ability 4 Exalted Ironbride -
Your Primary Weapon, release your true power! Orphix still take damage even if you attack from behind or on top of its head. Stay out from line of sight for Voidrig teamates. Dont Use this on sentient when its laser dancing.

• While leveling up [Bonewidow], 4th ability might not be available. Use range weapon like imperator vandal or mausolon or similar weapon, it is better for damaging Orphix.
• You may use [Fluctus] to shoot through the wall to destroy those Orphix Resonator. This is my to go weapon when 4th ability is ready up. Save a lot of time.